common: Move direct backports from GLib to a new translation unit

flatpak-utils.c is getting quite large, and is a mixture of code with
and without non-GLib dependencies, making it inconvenient to reuse in
other projects (like Steam's pressure-vessel) or link into Flatpak
services that don't need all of our dependencies (json-glib, appstream,
ostree). One obvious piece of low-hanging fruit for reducing the size
of this file is to move the GLib backports into their own
translation unit.

Sort them by GLib version, so that when we increase our GLib
dependency it's easy to delete the ones that are no longer applicable.

No functional changes intended in this commit.

Signed-off-by: Simon McVittie <smcv@collabora.com>

6 files changed, 916 insertions, 857 deletions

diff --git a/common/Makefile.am.inc b/common/Makefile.am.inc
index a6050289..5fa127ab 100644
--- a/common/Makefile.am.inc
+++ b/common/Makefile.am.inc
@@ -134,6 +134,8 @@ libflatpak_common_la_SOURCES = \
 	common/flatpak-error.c \
 	common/flatpak-exports-private.h \
 	common/flatpak-exports.c \
+	common/flatpak-glib-backports-private.h \
+	common/flatpak-glib-backports.c \
 	common/flatpak-installation-private.h \
 	common/flatpak-installation.c \
 	common/flatpak-installed-ref-private.h \
diff --git a/common/flatpak-glib-backports-private.h b/common/flatpak-glib-backports-private.h
new file mode 100644
index 00000000..1f42b9ac
--- /dev/null
+++ b/common/flatpak-glib-backports-private.h
@@ -0,0 +1,153 @@
+/*
+ * Copyright 2013 Allison Karlitskaya
+ * Copyright 2013 Collabora Ltd.
+ * Copyright 2016 Canonical Ltd.
+ * Copyright 2017-2018 Endless OS Foundation LLC
+ * Copyright 2019 Red Hat, Inc
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "libglnx.h"
+
+#include <glib.h>
+#include <gio/gio.h>
+#include <gio/gunixfdlist.h>
+
+/* Please sort this file by the GLib version where it originated,
+ * oldest first. */
+
+G_BEGIN_DECLS
+
+#if !GLIB_CHECK_VERSION (2, 40, 0)
+static inline gboolean
+g_key_file_save_to_file (GKeyFile    *key_file,
+                         const gchar *filename,
+                         GError     **error)
+{
+  gchar *contents;
+  gboolean success;
+  gsize length;
+
+  contents = g_key_file_to_data (key_file, &length, NULL);
+  success = g_file_set_contents (filename, contents, length, error);
+  g_free (contents);
+
+  return success;
+}
+#endif
+
+#if !GLIB_CHECK_VERSION (2, 43, 4)
+G_DEFINE_AUTOPTR_CLEANUP_FUNC (GUnixFDList, g_object_unref)
+#endif
+
+#if !GLIB_CHECK_VERSION (2, 54, 0)
+static inline gboolean
+g_ptr_array_find_with_equal_func (GPtrArray     *haystack,
+                                  gconstpointer  needle,
+                                  GEqualFunc     equal_func,
+                                  guint         *index_)
+{
+  guint i;
+
+  g_return_val_if_fail (haystack != NULL, FALSE);
+
+  if (equal_func == NULL)
+    equal_func = g_direct_equal;
+
+  for (i = 0; i < haystack->len; i++)
+    {
+      if (equal_func (g_ptr_array_index (haystack, i), needle))
+        {
+          if (index_ != NULL)
+            *index_ = i;
+          return TRUE;
+        }
+    }
+
+  return FALSE;
+}
+#endif
+
+#if !GLIB_CHECK_VERSION (2, 56, 0)
+typedef void (* GClearHandleFunc) (guint handle_id);
+
+static inline void
+g_clear_handle_id (guint            *tag_ptr,
+                   GClearHandleFunc  clear_func)
+{
+  guint _handle_id;
+
+  _handle_id = *tag_ptr;
+  if (_handle_id > 0)
+    {
+      *tag_ptr = 0;
+      clear_func (_handle_id);
+    }
+}
+
+GDateTime *flatpak_g_date_time_new_from_iso8601 (const gchar *text,
+                                                 GTimeZone   *default_tz);
+
+static inline GDateTime *
+g_date_time_new_from_iso8601 (const gchar *text, GTimeZone *default_tz)
+{
+  return flatpak_g_date_time_new_from_iso8601 (text, default_tz);
+}
+#endif
+
+#if !GLIB_CHECK_VERSION (2, 58, 0)
+static inline gboolean
+g_hash_table_steal_extended (GHashTable    *hash_table,
+                             gconstpointer  lookup_key,
+                             gpointer      *stolen_key,
+                             gpointer      *stolen_value)
+{
+  if (g_hash_table_lookup_extended (hash_table, lookup_key, stolen_key, stolen_value))
+    {
+      g_hash_table_steal (hash_table, lookup_key);
+      return TRUE;
+    }
+  else
+      return FALSE;
+}
+#endif
+
+#if !GLIB_CHECK_VERSION (2, 58, 0)
+const gchar * const *g_get_language_names_with_category (const gchar *category_name);
+#endif
+
+#if !GLIB_CHECK_VERSION (2, 62, 0)
+void g_ptr_array_extend (GPtrArray        *array_to_extend,
+                         GPtrArray        *array,
+                         GCopyFunc         func,
+                         gpointer          user_data);
+#endif
+
+#if !GLIB_CHECK_VERSION (2, 68, 0)
+guint g_string_replace (GString     *string,
+                        const gchar *find,
+                        const gchar *replace,
+                        guint        limit);
+#endif
+
+#ifndef G_DBUS_METHOD_INVOCATION_HANDLED    /* GLib < 2.68 */
+# define G_DBUS_METHOD_INVOCATION_HANDLED TRUE
+# define G_DBUS_METHOD_INVOCATION_UNHANDLED FALSE
+#endif
+
+G_END_DECLS
diff --git a/common/flatpak-glib-backports.c b/common/flatpak-glib-backports.c
new file mode 100644
index 00000000..912a6d9f
--- /dev/null
+++ b/common/flatpak-glib-backports.c
@@ -0,0 +1,759 @@
+/* vi:set et sw=2 sts=2 cin cino=t0,f0,(0,{s,>2s,n-s,^-s,e-s:
+ * Copyright 1995-1998 Free Software Foundation, Inc.
+ * Copyright 2004 Hidetoshi Tajima
+ * Copyright 2004-2010 Christian Persch
+ * Copyright 2004-2019 Red Hat, Inc
+ * Copyright 2016-2018 Canonical Ltd.
+ * Copyright 2019 Endless OS Foundation LLC
+ * Copyright 2019 Emmanuel Fleury
+ * Copyright 2021 Joshua Lee
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+#include "flatpak-glib-backports-private.h"
+
+#include <glib/gi18n-lib.h>
+
+/* Please sort this file by the GLib version where it originated,
+ * oldest first. */
+
+#if !GLIB_CHECK_VERSION (2, 56, 0)
+/* All this code is backported directly from glib */
+
+static void
+g_date_time_get_week_number (GDateTime *datetime,
+                             gint      *week_number,
+                             gint      *day_of_week,
+                             gint      *day_of_year)
+{
+  gint a, b, c, d, e, f, g, n, s, month, day, year;
+
+  g_date_time_get_ymd (datetime, &year, &month, &day);
+
+  if (month <= 2)
+    {
+      a = g_date_time_get_year (datetime) - 1;
+      b = (a / 4) - (a / 100) + (a / 400);
+      c = ((a - 1) / 4) - ((a - 1) / 100) + ((a - 1) / 400);
+      s = b - c;
+      e = 0;
+      f = day - 1 + (31 * (month - 1));
+    }
+  else
+    {
+      a = year;
+      b = (a / 4) - (a / 100) + (a / 400);
+      c = ((a - 1) / 4) - ((a - 1) / 100) + ((a - 1) / 400);
+      s = b - c;
+      e = s + 1;
+      f = day + (((153 * (month - 3)) + 2) / 5) + 58 + s;
+    }
+
+  g = (a + b) % 7;
+  d = (f + g - e) % 7;
+  n = f + 3 - d;
+
+  if (week_number)
+    {
+      if (n < 0)
+        *week_number = 53 - ((g - s) / 5);
+      else if (n > 364 + s)
+        *week_number = 1;
+      else
+        *week_number = (n / 7) + 1;
+    }
+
+  if (day_of_week)
+    *day_of_week = d + 1;
+
+  if (day_of_year)
+    *day_of_year = f + 1;
+}
+
+#define GREGORIAN_LEAP(y)    ((((y) % 4) == 0) && (!((((y) % 100) == 0) && (((y) % 400) != 0))))
+
+/* Parse integers in the form d (week days), dd (hours etc), ddd (ordinal days) or dddd (years) */
+static gboolean
+get_iso8601_int (const gchar *text, gsize length, gint *value)
+{
+  gint i, v = 0;
+
+  if (length < 1 || length > 4)
+    return FALSE;
+
+  for (i = 0; i < length; i++)
+    {
+      const gchar c = text[i];
+      if (c < '0' || c > '9')
+        return FALSE;
+      v = v * 10 + (c - '0');
+    }
+
+  *value = v;
+  return TRUE;
+}
+
+/* Parse seconds in the form ss or ss.sss (variable length decimal) */
+static gboolean
+get_iso8601_seconds (const gchar *text, gsize length, gdouble *value)
+{
+  gint i;
+  gdouble divisor = 1, v = 0;
+
+  if (length < 2)
+    return FALSE;
+
+  for (i = 0; i < 2; i++)
+    {
+      const gchar c = text[i];
+      if (c < '0' || c > '9')
+        return FALSE;
+      v = v * 10 + (c - '0');
+    }
+
+  if (length > 2 && !(text[i] == '.' || text[i] == ','))
+    return FALSE;
+  i++;
+  if (i == length)
+    return FALSE;
+
+  for (; i < length; i++)
+    {
+      const gchar c = text[i];
+      if (c < '0' || c > '9')
+        return FALSE;
+      v = v * 10 + (c - '0');
+      divisor *= 10;
+    }
+
+  *value = v / divisor;
+  return TRUE;
+}
+
+static GDateTime *
+g_date_time_new_ordinal (GTimeZone *tz, gint year, gint ordinal_day, gint hour, gint minute, gdouble seconds)
+{
+  GDateTime *dt, *dt2;
+
+  if (ordinal_day < 1 || ordinal_day > (GREGORIAN_LEAP (year) ? 366 : 365))
+    return NULL;
+
+  dt = g_date_time_new (tz, year, 1, 1, hour, minute, seconds);
+  dt2 = g_date_time_add_days (dt, ordinal_day - 1);
+  g_date_time_unref (dt);
+
+  return dt2;
+}
+
+static GDateTime *
+g_date_time_new_week (GTimeZone *tz, gint year, gint week, gint week_day, gint hour, gint minute, gdouble seconds)
+{
+  gint64 p;
+  gint max_week, jan4_week_day, ordinal_day;
+  GDateTime *dt;
+
+  p = (year * 365 + (year / 4) - (year / 100) + (year / 400)) % 7;
+  max_week = p == 4 ? 53 : 52;
+
+  if (week < 1 || week > max_week || week_day < 1 || week_day > 7)
+    return NULL;
+
+  dt = g_date_time_new (tz, year, 1, 4, 0, 0, 0);
+  g_date_time_get_week_number (dt, NULL, &jan4_week_day, NULL);
+  g_date_time_unref (dt);
+
+  ordinal_day = (week * 7) + week_day - (jan4_week_day + 3);
+  if (ordinal_day < 0)
+    {
+      year--;
+      ordinal_day += GREGORIAN_LEAP (year) ? 366 : 365;
+    }
+  else if (ordinal_day > (GREGORIAN_LEAP (year) ? 366 : 365))
+    {
+      ordinal_day -= (GREGORIAN_LEAP (year) ? 366 : 365);
+      year++;
+    }
+
+  return g_date_time_new_ordinal (tz, year, ordinal_day, hour, minute, seconds);
+}
+
+static GDateTime *
+parse_iso8601_date (const gchar *text, gsize length,
+                    gint hour, gint minute, gdouble seconds, GTimeZone *tz)
+{
+  /* YYYY-MM-DD */
+  if (length == 10 && text[4] == '-' && text[7] == '-')
+    {
+      int year, month, day;
+      if (!get_iso8601_int (text, 4, &year) ||
+          !get_iso8601_int (text + 5, 2, &month) ||
+          !get_iso8601_int (text + 8, 2, &day))
+        return NULL;
+      return g_date_time_new (tz, year, month, day, hour, minute, seconds);
+    }
+  /* YYYY-DDD */
+  else if (length == 8 && text[4] == '-')
+    {
+      gint year, ordinal_day;
+      if (!get_iso8601_int (text, 4, &year) ||
+          !get_iso8601_int (text + 5, 3, &ordinal_day))
+        return NULL;
+      return g_date_time_new_ordinal (tz, year, ordinal_day, hour, minute, seconds);
+    }
+  /* YYYY-Www-D */
+  else if (length == 10 && text[4] == '-' && text[5] == 'W' && text[8] == '-')
+    {
+      gint year, week, week_day;
+      if (!get_iso8601_int (text, 4, &year) ||
+          !get_iso8601_int (text + 6, 2, &week) ||
+          !get_iso8601_int (text + 9, 1, &week_day))
+        return NULL;
+      return g_date_time_new_week (tz, year, week, week_day, hour, minute, seconds);
+    }
+  /* YYYYWwwD */
+  else if (length == 8 && text[4] == 'W')
+    {
+      gint year, week, week_day;
+      if (!get_iso8601_int (text, 4, &year) ||
+          !get_iso8601_int (text + 5, 2, &week) ||
+          !get_iso8601_int (text + 7, 1, &week_day))
+        return NULL;
+      return g_date_time_new_week (tz, year, week, week_day, hour, minute, seconds);
+    }
+  /* YYYYMMDD */
+  else if (length == 8)
+    {
+      int year, month, day;
+      if (!get_iso8601_int (text, 4, &year) ||
+          !get_iso8601_int (text + 4, 2, &month) ||
+          !get_iso8601_int (text + 6, 2, &day))
+        return NULL;
+      return g_date_time_new (tz, year, month, day, hour, minute, seconds);
+    }
+  /* YYYYDDD */
+  else if (length == 7)
+    {
+      gint year, ordinal_day;
+      if (!get_iso8601_int (text, 4, &year) ||
+          !get_iso8601_int (text + 4, 3, &ordinal_day))
+        return NULL;
+      return g_date_time_new_ordinal (tz, year, ordinal_day, hour, minute, seconds);
+    }
+  else
+    return FALSE;
+}
+
+static GTimeZone *
+parse_iso8601_timezone (const gchar *text, gsize length, gssize *tz_offset)
+{
+  gint i, tz_length, offset_sign = 1, offset_hours, offset_minutes;
+  GTimeZone *tz;
+
+  /* UTC uses Z suffix  */
+  if (length > 0 && text[length - 1] == 'Z')
+    {
+      *tz_offset = length - 1;
+      return g_time_zone_new_utc ();
+    }
+
+  /* Look for '+' or '-' of offset */
+  for (i = length - 1; i >= 0; i--)
+    if (text[i] == '+' || text[i] == '-')
+      {
+        offset_sign = text[i] == '-' ? -1 : 1;
+        break;
+      }
+  if (i < 0)
+    return NULL;
+  tz_length = length - i;
+
+  /* +hh:mm or -hh:mm */
+  if (tz_length == 6 && text[i + 3] == ':')
+    {
+      if (!get_iso8601_int (text + i + 1, 2, &offset_hours) ||
+          !get_iso8601_int (text + i + 4, 2, &offset_minutes))
+        return NULL;
+    }
+  /* +hhmm or -hhmm */
+  else if (tz_length == 5)
+    {
+      if (!get_iso8601_int (text + i + 1, 2, &offset_hours) ||
+          !get_iso8601_int (text + i + 3, 2, &offset_minutes))
+        return NULL;
+    }
+  /* +hh or -hh */
+  else if (tz_length == 3)
+    {
+      if (!get_iso8601_int (text + i + 1, 2, &offset_hours))
+        return NULL;
+      offset_minutes = 0;
+    }
+  else
+    return NULL;
+
+  *tz_offset = i;
+  tz = g_time_zone_new (text + i);
+
+  /* Double-check that the GTimeZone matches our interpretation of the timezone.
+   * Failure would indicate a bug either here of in the GTimeZone code. */
+  g_assert (g_time_zone_get_offset (tz, 0) == offset_sign * (offset_hours * 3600 + offset_minutes * 60));
+
+  return tz;
+}
+
+static gboolean
+parse_iso8601_time (const gchar *text, gsize length,
+                    gint *hour, gint *minute, gdouble *seconds, GTimeZone **tz)
+{
+  gssize tz_offset = -1;
+
+  /* Check for timezone suffix */
+  *tz = parse_iso8601_timezone (text, length, &tz_offset);
+  if (tz_offset >= 0)
+    length = tz_offset;
+
+  /* hh:mm:ss(.sss) */
+  if (length >= 8 && text[2] == ':' && text[5] == ':')
+    {
+      return get_iso8601_int (text, 2, hour) &&
+             get_iso8601_int (text + 3, 2, minute) &&
+             get_iso8601_seconds (text + 6, length - 6, seconds);
+    }
+  /* hhmmss(.sss) */
+  else if (length >= 6)
+    {
+      return get_iso8601_int (text, 2, hour) &&
+             get_iso8601_int (text + 2, 2, minute) &&
+             get_iso8601_seconds (text + 4, length - 4, seconds);
+    }
+  else
+    return FALSE;
+}
+
+
+GDateTime *
+flatpak_g_date_time_new_from_iso8601 (const gchar *text, GTimeZone *default_tz)
+{
+  gint length, date_length = -1;
+  gint hour = 0, minute = 0;
+  gdouble seconds = 0.0;
+  GTimeZone *tz = NULL;
+  GDateTime *datetime = NULL;
+
+  g_return_val_if_fail (text != NULL, NULL);
+
+  /* Count length of string and find date / time separator ('T', 't', or ' ') */
+  for (length = 0; text[length] != '\0'; length++)
+    {
+      if (date_length < 0 && (text[length] == 'T' || text[length] == 't' || text[length] == ' '))
+        date_length = length;
+    }
+
+  if (date_length < 0)
+    return NULL;
+
+  if (!parse_iso8601_time (text + date_length + 1, length - (date_length + 1),
+                           &hour, &minute, &seconds, &tz))
+    goto out;
+  if (tz == NULL && default_tz == NULL)
+    return NULL;
+
+  datetime = parse_iso8601_date (text, date_length, hour, minute, seconds, tz ? tz : default_tz);
+
+out:
+  if (tz != NULL)
+    g_time_zone_unref (tz);
+  return datetime;
+}
+#endif
+
+#if !GLIB_CHECK_VERSION (2, 58, 0)
+/* All this code is backported directly from glib 2.66 */
+
+typedef struct _GLanguageNamesCache GLanguageNamesCache;
+
+struct _GLanguageNamesCache {
+  gchar *languages;
+  gchar **language_names;
+};
+
+static void
+language_names_cache_free (gpointer data)
+{
+  GLanguageNamesCache *cache = data;
+  g_free (cache->languages);
+  g_strfreev (cache->language_names);
+  g_free (cache);
+}
+
+/* read an alias file for the locales */
+static void
+read_aliases (const gchar *file,
+              GHashTable  *alias_table)
+{
+  FILE *fp;
+  char buf[256];
+
+  fp = fopen (file,"r");
+  if (!fp)
+    return;
+  while (fgets (buf, 256, fp))
+    {
+      char *p, *q;
+
+      g_strstrip (buf);
+
+      /* Line is a comment */
+      if ((buf[0] == '#') || (buf[0] == '\0'))
+        continue;
+
+      /* Reads first column */
+      for (p = buf, q = NULL; *p; p++) {
+        if ((*p == '\t') || (*p == ' ') || (*p == ':')) {
+          *p = '\0';
+          q = p+1;
+          while ((*q == '\t') || (*q == ' ')) {
+            q++;
+          }
+          break;
+        }
+      }
+      /* The line only had one column */
+      if (!q || *q == '\0')
+        continue;
+
+      /* Read second column */
+      for (p = q; *p; p++) {
+        if ((*p == '\t') || (*p == ' ')) {
+          *p = '\0';
+          break;
+        }
+      }
+
+      /* Add to alias table if necessary */
+      if (!g_hash_table_lookup (alias_table, buf)) {
+        g_hash_table_insert (alias_table, g_strdup (buf), g_strdup (q));
+      }
+    }
+  fclose (fp);
+}
+
+static char *
+unalias_lang (char *lang)
+{
+  static GHashTable *alias_table = NULL;
+  char *p;
+  int i;
+
+  if (g_once_init_enter (&alias_table))
+    {
+      GHashTable *table = g_hash_table_new (g_str_hash, g_str_equal);
+      read_aliases ("/usr/share/locale/locale.alias", table);
+      g_once_init_leave (&alias_table, table);
+    }
+
+  i = 0;
+  while ((p = g_hash_table_lookup (alias_table, lang)) && (strcmp (p, lang) != 0))
+    {
+      lang = p;
+      if (i++ == 30)
+        {
+          static gboolean said_before = FALSE;
+          if (!said_before)
+            g_warning ("Too many alias levels for a locale, "
+                       "may indicate a loop");
+          said_before = TRUE;
+          return lang;
+        }
+    }
+  return lang;
+}
+
+/* Mask for components of locale spec. The ordering here is from
+ * least significant to most significant
+ */
+enum
+{
+  COMPONENT_CODESET =   1 << 0,
+  COMPONENT_TERRITORY = 1 << 1,
+  COMPONENT_MODIFIER =  1 << 2
+};
+
+/* Break an X/Open style locale specification into components
+ */
+static guint
+explode_locale (const gchar *locale,
+                gchar      **language,
+                gchar      **territory,
+                gchar      **codeset,
+                gchar      **modifier)
+{
+  const gchar *uscore_pos;
+  const gchar *at_pos;
+  const gchar *dot_pos;
+
+  guint mask = 0;
+
+  uscore_pos = strchr (locale, '_');
+  dot_pos = strchr (uscore_pos ? uscore_pos : locale, '.');
+  at_pos = strchr (dot_pos ? dot_pos : (uscore_pos ? uscore_pos : locale), '@');
+
+  if (at_pos)
+    {
+      mask |= COMPONENT_MODIFIER;
+      *modifier = g_strdup (at_pos);
+    }
+  else
+    at_pos = locale + strlen (locale);
+
+  if (dot_pos)
+    {
+      mask |= COMPONENT_CODESET;
+      *codeset = g_strndup (dot_pos, at_pos - dot_pos);
+    }
+  else
+    dot_pos = at_pos;
+
+  if (uscore_pos)
+    {
+      mask |= COMPONENT_TERRITORY;
+      *territory = g_strndup (uscore_pos, dot_pos - uscore_pos);
+    }
+  else
+    uscore_pos = dot_pos;
+
+  *language = g_strndup (locale, uscore_pos - locale);
+
+  return mask;
+}
+
+/*
+ * Compute all interesting variants for a given locale name -
+ * by stripping off different components of the value.
+ *
+ * For simplicity, we assume that the locale is in
+ * X/Open format: language[_territory][.codeset][@modifier]
+ *
+ * TODO: Extend this to handle the CEN format (see the GNUlibc docs)
+ *       as well. We could just copy the code from glibc wholesale
+ *       but it is big, ugly, and complicated, so I'm reluctant
+ *       to do so when this should handle 99% of the time...
+ */
+static void
+append_locale_variants (GPtrArray *array,
+                        const gchar *locale)
+{
+  gchar *language = NULL;
+  gchar *territory = NULL;
+  gchar *codeset = NULL;
+  gchar *modifier = NULL;
+
+  guint mask;
+  guint i, j;
+
+  g_return_if_fail (locale != NULL);
+
+  mask = explode_locale (locale, &language, &territory, &codeset, &modifier);
+
+  /* Iterate through all possible combinations, from least attractive
+   * to most attractive.
+   */
+  for (j = 0; j <= mask; ++j)
+    {
+      i = mask - j;
+
+      if ((i & ~mask) == 0)
+        {
+          gchar *val = g_strconcat (language,
+                                    (i & COMPONENT_TERRITORY) ? territory : "",
+                                    (i & COMPONENT_CODESET) ? codeset : "",
+                                    (i & COMPONENT_MODIFIER) ? modifier : "",
+                                    NULL);
+          g_ptr_array_add (array, val);
+        }
+    }
+
+  g_free (language);
+  if (mask & COMPONENT_CODESET)
+    g_free (codeset);
+  if (mask & COMPONENT_TERRITORY)
+    g_free (territory);
+  if (mask & COMPONENT_MODIFIER)
+    g_free (modifier);
+}
+
+/* The following is (partly) taken from the gettext package.
+   Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.  */
+
+static const gchar *
+guess_category_value (const gchar *category_name)
+{
+  const gchar *retval;
+
+  /* The highest priority value is the 'LANGUAGE' environment
+     variable.  This is a GNU extension.  */
+  retval = g_getenv ("LANGUAGE");
+  if ((retval != NULL) && (retval[0] != '\0'))
+    return retval;
+
+  /* 'LANGUAGE' is not set.  So we have to proceed with the POSIX
+     methods of looking to 'LC_ALL', 'LC_xxx', and 'LANG'.  On some
+     systems this can be done by the 'setlocale' function itself.  */
+
+  /* Setting of LC_ALL overwrites all other.  */
+  retval = g_getenv ("LC_ALL");
+  if ((retval != NULL) && (retval[0] != '\0'))
+    return retval;
+
+  /* Next comes the name of the desired category.  */
+  retval = g_getenv (category_name);
+  if ((retval != NULL) && (retval[0] != '\0'))
+    return retval;
+
+  /* Last possibility is the LANG environment variable.  */
+  retval = g_getenv ("LANG");
+  if ((retval != NULL) && (retval[0] != '\0'))
+    return retval;
+
+#ifdef G_PLATFORM_WIN32
+  /* g_win32_getlocale() first checks for LC_ALL, LC_MESSAGES and
+   * LANG, which we already did above. Oh well. The main point of
+   * calling g_win32_getlocale() is to get the thread's locale as used
+   * by Windows and the Microsoft C runtime (in the "English_United
+   * States" format) translated into the Unixish format.
+   */
+  {
+    char *locale = g_win32_getlocale ();
+    retval = g_intern_string (locale);
+    g_free (locale);
+    return retval;
+  }
+#endif
+
+  return NULL;
+}
+
+const gchar * const *
+g_get_language_names_with_category (const gchar *category_name)
+{
+  static GPrivate cache_private = G_PRIVATE_INIT ((void (*)(gpointer)) g_hash_table_unref);
+  GHashTable *cache = g_private_get (&cache_private);
+  const gchar *languages;
+  GLanguageNamesCache *name_cache;
+
+  g_return_val_if_fail (category_name != NULL, NULL);
+
+  if (!cache)
+    {
+      cache = g_hash_table_new_full (g_str_hash, g_str_equal,
+                                     g_free, language_names_cache_free);
+      g_private_set (&cache_private, cache);
+    }
+
+  languages = guess_category_value (category_name);
+  if (!languages)
+    languages = "C";
+
+  name_cache = (GLanguageNamesCache *) g_hash_table_lookup (cache, category_name);
+  if (!(name_cache && name_cache->languages &&
+        strcmp (name_cache->languages, languages) == 0))
+    {
+      GPtrArray *array;
+      gchar **alist, **a;
+
+      g_hash_table_remove (cache, category_name);
+
+      array = g_ptr_array_sized_new (8);
+
+      alist = g_strsplit (languages, ":", 0);
+      for (a = alist; *a; a++)
+        append_locale_variants (array, unalias_lang (*a));
+      g_strfreev (alist);
+      g_ptr_array_add (array, g_strdup ("C"));
+      g_ptr_array_add (array, NULL);
+
+      name_cache = g_new0 (GLanguageNamesCache, 1);
+      name_cache->languages = g_strdup (languages);
+      name_cache->language_names = (gchar **) g_ptr_array_free (array, FALSE);
+      g_hash_table_insert (cache, g_strdup (category_name), name_cache);
+    }
+
+  return (const gchar * const *) name_cache->language_names;
+}
+#endif
+
+#if !GLIB_CHECK_VERSION (2, 62, 0)
+void
+g_ptr_array_extend (GPtrArray  *array_to_extend,
+                    GPtrArray  *array,
+                    GCopyFunc   func,
+                    gpointer    user_data)
+{
+  for (gsize i = 0; i < array->len; i++)
+    {
+      if (func)
+        g_ptr_array_add (array_to_extend, func (g_ptr_array_index (array, i), user_data));
+      else
+        g_ptr_array_add (array_to_extend, g_ptr_array_index (array, i));
+    }
+}
+#endif
+
+#if !GLIB_CHECK_VERSION (2, 68, 0)
+/* All this code is backported directly from glib */
+guint
+g_string_replace (GString     *string,
+                  const gchar *find,
+                  const gchar *replace,
+                  guint        limit)
+{
+  gsize f_len, r_len, pos;
+  gchar *cur, *next;
+  guint n = 0;
+
+  g_return_val_if_fail (string != NULL, 0);
+  g_return_val_if_fail (find != NULL, 0);
+  g_return_val_if_fail (replace != NULL, 0);
+
+  f_len = strlen (find);
+  r_len = strlen (replace);
+  cur = string->str;
+
+  while ((next = strstr (cur, find)) != NULL)
+    {
+      pos = next - string->str;
+      g_string_erase (string, pos, f_len);
+      g_string_insert (string, pos, replace);
+      cur = string->str + pos + r_len;
+      n++;
+      /* Only match the empty string once at any given position, to
+       * avoid infinite loops */
+      if (f_len == 0)
+        {
+          if (cur[0] == '\0')
+            break;
+          else
+            cur++;
+        }
+      if (n == limit)
+        break;
+    }
+
+  return n;
+}
+
+#endif /* GLIB_CHECK_VERSION (2, 68, 0) */
diff --git a/common/flatpak-utils-private.h b/common/flatpak-utils-private.h
index b37302f0..7de1233c 100644
--- a/common/flatpak-utils-private.h
+++ b/common/flatpak-utils-private.h
@@ -31,6 +31,7 @@
 #include "flatpak-document-dbus-generated.h"
 #include "flatpak-context-private.h"
 #include "flatpak-error.h"
+#include "flatpak-glib-backports-private.h"
 #include "flatpak-utils-http-private.h"
 #include "flatpak-variant-private.h"
 #include "flatpak-dir-private.h"
@@ -247,130 +248,6 @@ gboolean flatpak_utils_ascii_string_to_unsigned (const gchar *str,
                                                  guint64     *out_num,
                                                  GError     **error);
 
-
-#if !GLIB_CHECK_VERSION (2, 40, 0)
-static inline gboolean
-g_key_file_save_to_file (GKeyFile    *key_file,
-                         const gchar *filename,
-                         GError     **error)
-{
-  gchar *contents;
-  gboolean success;
-  gsize length;
-
-  contents = g_key_file_to_data (key_file, &length, NULL);
-  success = g_file_set_contents (filename, contents, length, error);
-  g_free (contents);
-
-  return success;
-}
-#endif
-
-#if !GLIB_CHECK_VERSION (2, 50, 0)
-static inline gboolean
-g_key_file_load_from_bytes (GKeyFile     *key_file,
-                            GBytes       *bytes,
-                            GKeyFileFlags flags,
-                            GError      **error)
-{
-  const guchar *data;
-  gsize size;
-
-  data = g_bytes_get_data (bytes, &size);
-  return g_key_file_load_from_data (key_file, (const gchar *) data, size, flags, error);
-}
-#endif
-
-#if !GLIB_CHECK_VERSION (2, 54, 0)
-static inline gboolean
-g_ptr_array_find_with_equal_func (GPtrArray     *haystack,
-                                  gconstpointer  needle,
-                                  GEqualFunc     equal_func,
-                                  guint         *index_)
-{
-  guint i;
-
-  g_return_val_if_fail (haystack != NULL, FALSE);
-
-  if (equal_func == NULL)
-    equal_func = g_direct_equal;
-
-  for (i = 0; i < haystack->len; i++)
-    {
-      if (equal_func (g_ptr_array_index (haystack, i), needle))
-        {
-          if (index_ != NULL)
-            *index_ = i;
-          return TRUE;
-        }
-    }
-
-  return FALSE;
-}
-#endif
-
-#if !GLIB_CHECK_VERSION (2, 56, 0)
-GDateTime *flatpak_g_date_time_new_from_iso8601 (const gchar *text,
-                                                 GTimeZone   *default_tz);
-
-static inline GDateTime *
-g_date_time_new_from_iso8601 (const gchar *text, GTimeZone *default_tz)
-{
-  return flatpak_g_date_time_new_from_iso8601 (text, default_tz);
-}
-#endif
-
-
-#if !GLIB_CHECK_VERSION (2, 56, 0)
-typedef void (* GClearHandleFunc) (guint handle_id);
-
-static inline void
-g_clear_handle_id (guint            *tag_ptr,
-                   GClearHandleFunc  clear_func)
-{
-  guint _handle_id;
-
-  _handle_id = *tag_ptr;
-  if (_handle_id > 0)
-    {
-      *tag_ptr = 0;
-      clear_func (_handle_id);
-    }
-}
-#endif
-
-
-#if !GLIB_CHECK_VERSION (2, 58, 0)
-static inline gboolean
-g_hash_table_steal_extended (GHashTable    *hash_table,
-                             gconstpointer  lookup_key,
-                             gpointer      *stolen_key,
-                             gpointer      *stolen_value)
-{
-  if (g_hash_table_lookup_extended (hash_table, lookup_key, stolen_key, stolen_value))
-    {
-      g_hash_table_steal (hash_table, lookup_key);
-      return TRUE;
-    }
-  else
-      return FALSE;
-}
-#endif
-
-#if !GLIB_CHECK_VERSION (2, 62, 0)
-void g_ptr_array_extend (GPtrArray        *array_to_extend,
-                         GPtrArray        *array,
-                         GCopyFunc         func,
-                         gpointer          user_data);
-#endif
-
-#if !GLIB_CHECK_VERSION (2, 68, 0)
-guint g_string_replace (GString     *string,
-                        const gchar *find,
-                        const gchar *replace,
-                        guint        limit);
-#endif
-
 gboolean flatpak_g_ptr_array_contains_string (GPtrArray  *array,
                                               const char *str);
 
@@ -758,10 +635,6 @@ G_DEFINE_AUTOPTR_CLEANUP_FUNC (JsonPath, g_object_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC (JsonReader, g_object_unref)
 #endif
 
-#if !GLIB_CHECK_VERSION (2, 43, 4)
-G_DEFINE_AUTOPTR_CLEANUP_FUNC (GUnixFDList, g_object_unref)
-#endif
-
 /* This uses a weird Auto prefix to avoid conflicts with later added autogenerated autoptr support, per:
  * https://git.gnome.org/browse/glib/commit/?id=1c6cd5f0a3104aa9b62c7f1d3086181f63e71b59
  */
diff --git a/common/flatpak-utils.c b/common/flatpak-utils.c
index b8ad9700..3e8b895d 100644
--- a/common/flatpak-utils.c
+++ b/common/flatpak-utils.c
@@ -7896,322 +7896,6 @@ flatpak_g_ptr_array_contains_string (GPtrArray *array, const char *str)
   return FALSE;
 }
 
-#if !GLIB_CHECK_VERSION (2, 58, 0)
-/* All this code is backported directly from glib 2.66 */
-
-typedef struct _GLanguageNamesCache GLanguageNamesCache;
-
-struct _GLanguageNamesCache {
-  gchar *languages;
-  gchar **language_names;
-};
-
-static void
-language_names_cache_free (gpointer data)
-{
-  GLanguageNamesCache *cache = data;
-  g_free (cache->languages);
-  g_strfreev (cache->language_names);
-  g_free (cache);
-}
-
-/* read an alias file for the locales */
-static void
-read_aliases (const gchar *file,
-              GHashTable  *alias_table)
-{
-  FILE *fp;
-  char buf[256];
-
-  fp = fopen (file,"r");
-  if (!fp)
-    return;
-  while (fgets (buf, 256, fp))
-    {
-      char *p, *q;
-
-      g_strstrip (buf);
-
-      /* Line is a comment */
-      if ((buf[0] == '#') || (buf[0] == '\0'))
-        continue;
-
-      /* Reads first column */
-      for (p = buf, q = NULL; *p; p++) {
-        if ((*p == '\t') || (*p == ' ') || (*p == ':')) {
-          *p = '\0';
-          q = p+1;
-          while ((*q == '\t') || (*q == ' ')) {
-            q++;
-          }
-          break;
-        }
-      }
-      /* The line only had one column */
-      if (!q || *q == '\0')
-        continue;
-
-      /* Read second column */
-      for (p = q; *p; p++) {
-        if ((*p == '\t') || (*p == ' ')) {
-          *p = '\0';
-          break;
-        }
-      }
-
-      /* Add to alias table if necessary */
-      if (!g_hash_table_lookup (alias_table, buf)) {
-        g_hash_table_insert (alias_table, g_strdup (buf), g_strdup (q));
-      }
-    }
-  fclose (fp);
-}
-
-static char *
-unalias_lang (char *lang)
-{
-  static GHashTable *alias_table = NULL;
-  char *p;
-  int i;
-
-  if (g_once_init_enter (&alias_table))
-    {
-      GHashTable *table = g_hash_table_new (g_str_hash, g_str_equal);
-      read_aliases ("/usr/share/locale/locale.alias", table);
-      g_once_init_leave (&alias_table, table);
-    }
-
-  i = 0;
-  while ((p = g_hash_table_lookup (alias_table, lang)) && (strcmp (p, lang) != 0))
-    {
-      lang = p;
-      if (i++ == 30)
-        {
-          static gboolean said_before = FALSE;
-          if (!said_before)
-            g_warning ("Too many alias levels for a locale, "
-                       "may indicate a loop");
-          said_before = TRUE;
-          return lang;
-        }
-    }
-  return lang;
-}
-
-/* Mask for components of locale spec. The ordering here is from
- * least significant to most significant
- */
-enum
-{
-  COMPONENT_CODESET =   1 << 0,
-  COMPONENT_TERRITORY = 1 << 1,
-  COMPONENT_MODIFIER =  1 << 2
-};
-
-/* Break an X/Open style locale specification into components
- */
-static guint
-explode_locale (const gchar *locale,
-                gchar      **language,
-                gchar      **territory,
-                gchar      **codeset,
-                gchar      **modifier)
-{
-  const gchar *uscore_pos;
-  const gchar *at_pos;
-  const gchar *dot_pos;
-
-  guint mask = 0;
-
-  uscore_pos = strchr (locale, '_');
-  dot_pos = strchr (uscore_pos ? uscore_pos : locale, '.');
-  at_pos = strchr (dot_pos ? dot_pos : (uscore_pos ? uscore_pos : locale), '@');
-
-  if (at_pos)
-    {
-      mask |= COMPONENT_MODIFIER;
-      *modifier = g_strdup (at_pos);
-    }
-  else
-    at_pos = locale + strlen (locale);
-
-  if (dot_pos)
-    {
-      mask |= COMPONENT_CODESET;
-      *codeset = g_strndup (dot_pos, at_pos - dot_pos);
-    }
-  else
-    dot_pos = at_pos;
-
-  if (uscore_pos)
-    {
-      mask |= COMPONENT_TERRITORY;
-      *territory = g_strndup (uscore_pos, dot_pos - uscore_pos);
-    }
-  else
-    uscore_pos = dot_pos;
-
-  *language = g_strndup (locale, uscore_pos - locale);
-
-  return mask;
-}
-
-/*
- * Compute all interesting variants for a given locale name -
- * by stripping off different components of the value.
- *
- * For simplicity, we assume that the locale is in
- * X/Open format: language[_territory][.codeset][@modifier]
- *
- * TODO: Extend this to handle the CEN format (see the GNUlibc docs)
- *       as well. We could just copy the code from glibc wholesale
- *       but it is big, ugly, and complicated, so I'm reluctant
- *       to do so when this should handle 99% of the time...
- */
-static void
-append_locale_variants (GPtrArray *array,
-                        const gchar *locale)
-{
-  gchar *language = NULL;
-  gchar *territory = NULL;
-  gchar *codeset = NULL;
-  gchar *modifier = NULL;
-
-  guint mask;
-  guint i, j;
-
-  g_return_if_fail (locale != NULL);
-
-  mask = explode_locale (locale, &language, &territory, &codeset, &modifier);
-
-  /* Iterate through all possible combinations, from least attractive
-   * to most attractive.
-   */
-  for (j = 0; j <= mask; ++j)
-    {
-      i = mask - j;
-
-      if ((i & ~mask) == 0)
-        {
-          gchar *val = g_strconcat (language,
-                                    (i & COMPONENT_TERRITORY) ? territory : "",
-                                    (i & COMPONENT_CODESET) ? codeset : "",
-                                    (i & COMPONENT_MODIFIER) ? modifier : "",
-                                    NULL);
-          g_ptr_array_add (array, val);
-        }
-    }
-
-  g_free (language);
-  if (mask & COMPONENT_CODESET)
-    g_free (codeset);
-  if (mask & COMPONENT_TERRITORY)
-    g_free (territory);
-  if (mask & COMPONENT_MODIFIER)
-    g_free (modifier);
-}
-
-/* The following is (partly) taken from the gettext package.
-   Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.  */
-
-static const gchar *
-guess_category_value (const gchar *category_name)
-{
-  const gchar *retval;
-
-  /* The highest priority value is the 'LANGUAGE' environment
-     variable.  This is a GNU extension.  */
-  retval = g_getenv ("LANGUAGE");
-  if ((retval != NULL) && (retval[0] != '\0'))
-    return retval;
-
-  /* 'LANGUAGE' is not set.  So we have to proceed with the POSIX
-     methods of looking to 'LC_ALL', 'LC_xxx', and 'LANG'.  On some
-     systems this can be done by the 'setlocale' function itself.  */
-
-  /* Setting of LC_ALL overwrites all other.  */
-  retval = g_getenv ("LC_ALL");
-  if ((retval != NULL) && (retval[0] != '\0'))
-    return retval;
-
-  /* Next comes the name of the desired category.  */
-  retval = g_getenv (category_name);
-  if ((retval != NULL) && (retval[0] != '\0'))
-    return retval;
-
-  /* Last possibility is the LANG environment variable.  */
-  retval = g_getenv ("LANG");
-  if ((retval != NULL) && (retval[0] != '\0'))
-    return retval;
-
-#ifdef G_PLATFORM_WIN32
-  /* g_win32_getlocale() first checks for LC_ALL, LC_MESSAGES and
-   * LANG, which we already did above. Oh well. The main point of
-   * calling g_win32_getlocale() is to get the thread's locale as used
-   * by Windows and the Microsoft C runtime (in the "English_United
-   * States" format) translated into the Unixish format.
-   */
-  {
-    char *locale = g_win32_getlocale ();
-    retval = g_intern_string (locale);
-    g_free (locale);
-    return retval;
-  }
-#endif
-
-  return NULL;
-}
-
-static const gchar * const *
-g_get_language_names_with_category (const gchar *category_name)
-{
-  static GPrivate cache_private = G_PRIVATE_INIT ((void (*)(gpointer)) g_hash_table_unref);
-  GHashTable *cache = g_private_get (&cache_private);
-  const gchar *languages;
-  GLanguageNamesCache *name_cache;
-
-  g_return_val_if_fail (category_name != NULL, NULL);
-
-  if (!cache)
-    {
-      cache = g_hash_table_new_full (g_str_hash, g_str_equal,
-                                     g_free, language_names_cache_free);
-      g_private_set (&cache_private, cache);
-    }
-
-  languages = guess_category_value (category_name);
-  if (!languages)
-    languages = "C";
-
-  name_cache = (GLanguageNamesCache *) g_hash_table_lookup (cache, category_name);
-  if (!(name_cache && name_cache->languages &&
-        strcmp (name_cache->languages, languages) == 0))
-    {
-      GPtrArray *array;
-      gchar **alist, **a;
-
-      g_hash_table_remove (cache, category_name);
-
-      array = g_ptr_array_sized_new (8);
-
-      alist = g_strsplit (languages, ":", 0);
-      for (a = alist; *a; a++)
-        append_locale_variants (array, unalias_lang (*a));
-      g_strfreev (alist);
-      g_ptr_array_add (array, g_strdup ("C"));
-      g_ptr_array_add (array, NULL);
-
-      name_cache = g_new0 (GLanguageNamesCache, 1);
-      name_cache->languages = g_strdup (languages);
-      name_cache->language_names = (gchar **) g_ptr_array_free (array, FALSE);
-      g_hash_table_insert (cache, g_strdup (category_name), name_cache);
-    }
-
-  return (const gchar * const *) name_cache->language_names;
-}
-
-#endif
-
 char **
 flatpak_get_current_locale_langs (void)
 {
@@ -8656,357 +8340,6 @@ flatpak_repo_resolve_rev (OstreeRepo    *repo,
   return TRUE;
 }
 
-
-#if !GLIB_CHECK_VERSION (2, 56, 0)
-/* All this code is backported directly from glib */
-
-static void
-g_date_time_get_week_number (GDateTime *datetime,
-                             gint      *week_number,
-                             gint      *day_of_week,
-                             gint      *day_of_year)
-{
-  gint a, b, c, d, e, f, g, n, s, month, day, year;
-
-  g_date_time_get_ymd (datetime, &year, &month, &day);
-
-  if (month <= 2)
-    {
-      a = g_date_time_get_year (datetime) - 1;
-      b = (a / 4) - (a / 100) + (a / 400);
-      c = ((a - 1) / 4) - ((a - 1) / 100) + ((a - 1) / 400);
-      s = b - c;
-      e = 0;
-      f = day - 1 + (31 * (month - 1));
-    }
-  else
-    {
-      a = year;
-      b = (a / 4) - (a / 100) + (a / 400);
-      c = ((a - 1) / 4) - ((a - 1) / 100) + ((a - 1) / 400);
-      s = b - c;
-      e = s + 1;
-      f = day + (((153 * (month - 3)) + 2) / 5) + 58 + s;
-    }
-
-  g = (a + b) % 7;
-  d = (f + g - e) % 7;
-  n = f + 3 - d;
-
-  if (week_number)
-    {
-      if (n < 0)
-        *week_number = 53 - ((g - s) / 5);
-      else if (n > 364 + s)
-        *week_number = 1;
-      else
-        *week_number = (n / 7) + 1;
-    }
-
-  if (day_of_week)
-    *day_of_week = d + 1;
-
-  if (day_of_year)
-    *day_of_year = f + 1;
-}
-
-#define GREGORIAN_LEAP(y)    ((((y) % 4) == 0) && (!((((y) % 100) == 0) && (((y) % 400) != 0))))
-
-/* Parse integers in the form d (week days), dd (hours etc), ddd (ordinal days) or dddd (years) */
-static gboolean
-get_iso8601_int (const gchar *text, gsize length, gint *value)
-{
-  gint i, v = 0;
-
-  if (length < 1 || length > 4)
-    return FALSE;
-
-  for (i = 0; i < length; i++)
-    {
-      const gchar c = text[i];
-      if (c < '0' || c > '9')
-        return FALSE;
-      v = v * 10 + (c - '0');
-    }
-
-  *value = v;
-  return TRUE;
-}
-
-/* Parse seconds in the form ss or ss.sss (variable length decimal) */
-static gboolean
-get_iso8601_seconds (const gchar *text, gsize length, gdouble *value)
-{
-  gint i;
-  gdouble divisor = 1, v = 0;
-
-  if (length < 2)
-    return FALSE;
-
-  for (i = 0; i < 2; i++)
-    {
-      const gchar c = text[i];
-      if (c < '0' || c > '9')
-        return FALSE;
-      v = v * 10 + (c - '0');
-    }
-
-  if (length > 2 && !(text[i] == '.' || text[i] == ','))
-    return FALSE;
-  i++;
-  if (i == length)
-    return FALSE;
-
-  for (; i < length; i++)
-    {
-      const gchar c = text[i];
-      if (c < '0' || c > '9')
-        return FALSE;
-      v = v * 10 + (c - '0');
-      divisor *= 10;
-    }
-
-  *value = v / divisor;
-  return TRUE;
-}
-
-static GDateTime *
-g_date_time_new_ordinal (GTimeZone *tz, gint year, gint ordinal_day, gint hour, gint minute, gdouble seconds)
-{
-  GDateTime *dt, *dt2;
-
-  if (ordinal_day < 1 || ordinal_day > (GREGORIAN_LEAP (year) ? 366 : 365))
-    return NULL;
-
-  dt = g_date_time_new (tz, year, 1, 1, hour, minute, seconds);
-  dt2 = g_date_time_add_days (dt, ordinal_day - 1);
-  g_date_time_unref (dt);
-
-  return dt2;
-}
-
-static GDateTime *
-g_date_time_new_week (GTimeZone *tz, gint year, gint week, gint week_day, gint hour, gint minute, gdouble seconds)
-{
-  gint64 p;
-  gint max_week, jan4_week_day, ordinal_day;
-  GDateTime *dt;
-
-  p = (year * 365 + (year / 4) - (year / 100) + (year / 400)) % 7;
-  max_week = p == 4 ? 53 : 52;
-
-  if (week < 1 || week > max_week || week_day < 1 || week_day > 7)
-    return NULL;
-
-  dt = g_date_time_new (tz, year, 1, 4, 0, 0, 0);
-  g_date_time_get_week_number (dt, NULL, &jan4_week_day, NULL);
-  g_date_time_unref (dt);
-
-  ordinal_day = (week * 7) + week_day - (jan4_week_day + 3);
-  if (ordinal_day < 0)
-    {
-      year--;
-      ordinal_day += GREGORIAN_LEAP (year) ? 366 : 365;
-    }
-  else if (ordinal_day > (GREGORIAN_LEAP (year) ? 366 : 365))
-    {
-      ordinal_day -= (GREGORIAN_LEAP (year) ? 366 : 365);
-      year++;
-    }
-
-  return g_date_time_new_ordinal (tz, year, ordinal_day, hour, minute, seconds);
-}
-
-static GDateTime *
-parse_iso8601_date (const gchar *text, gsize length,
-                    gint hour, gint minute, gdouble seconds, GTimeZone *tz)
-{
-  /* YYYY-MM-DD */
-  if (length == 10 && text[4] == '-' && text[7] == '-')
-    {
-      int year, month, day;
-      if (!get_iso8601_int (text, 4, &year) ||
-          !get_iso8601_int (text + 5, 2, &month) ||
-          !get_iso8601_int (text + 8, 2, &day))
-        return NULL;
-      return g_date_time_new (tz, year, month, day, hour, minute, seconds);
-    }
-  /* YYYY-DDD */
-  else if (length == 8 && text[4] == '-')
-    {
-      gint year, ordinal_day;
-      if (!get_iso8601_int (text, 4, &year) ||
-          !get_iso8601_int (text + 5, 3, &ordinal_day))
-        return NULL;
-      return g_date_time_new_ordinal (tz, year, ordinal_day, hour, minute, seconds);
-    }
-  /* YYYY-Www-D */
-  else if (length == 10 && text[4] == '-' && text[5] == 'W' && text[8] == '-')
-    {
-      gint year, week, week_day;
-      if (!get_iso8601_int (text, 4, &year) ||
-          !get_iso8601_int (text + 6, 2, &week) ||
-          !get_iso8601_int (text + 9, 1, &week_day))
-        return NULL;
-      return g_date_time_new_week (tz, year, week, week_day, hour, minute, seconds);
-    }
-  /* YYYYWwwD */
-  else if (length == 8 && text[4] == 'W')
-    {
-      gint year, week, week_day;
-      if (!get_iso8601_int (text, 4, &year) ||
-          !get_iso8601_int (text + 5, 2, &week) ||
-          !get_iso8601_int (text + 7, 1, &week_day))
-        return NULL;
-      return g_date_time_new_week (tz, year, week, week_day, hour, minute, seconds);
-    }
-  /* YYYYMMDD */
-  else if (length == 8)
-    {
-      int year, month, day;
-      if (!get_iso8601_int (text, 4, &year) ||
-          !get_iso8601_int (text + 4, 2, &month) ||
-          !get_iso8601_int (text + 6, 2, &day))
-        return NULL;
-      return g_date_time_new (tz, year, month, day, hour, minute, seconds);
-    }
-  /* YYYYDDD */
-  else if (length == 7)
-    {
-      gint year, ordinal_day;
-      if (!get_iso8601_int (text, 4, &year) ||
-          !get_iso8601_int (text + 4, 3, &ordinal_day))
-        return NULL;
-      return g_date_time_new_ordinal (tz, year, ordinal_day, hour, minute, seconds);
-    }
-  else
-    return FALSE;
-}
-
-static GTimeZone *
-parse_iso8601_timezone (const gchar *text, gsize length, gssize *tz_offset)
-{
-  gint i, tz_length, offset_sign = 1, offset_hours, offset_minutes;
-  GTimeZone *tz;
-
-  /* UTC uses Z suffix  */
-  if (length > 0 && text[length - 1] == 'Z')
-    {
-      *tz_offset = length - 1;
-      return g_time_zone_new_utc ();
-    }
-
-  /* Look for '+' or '-' of offset */
-  for (i = length - 1; i >= 0; i--)
-    if (text[i] == '+' || text[i] == '-')
-      {
-        offset_sign = text[i] == '-' ? -1 : 1;
-        break;
-      }
-  if (i < 0)
-    return NULL;
-  tz_length = length - i;
-
-  /* +hh:mm or -hh:mm */
-  if (tz_length == 6 && text[i + 3] == ':')
-    {
-      if (!get_iso8601_int (text + i + 1, 2, &offset_hours) ||
-          !get_iso8601_int (text + i + 4, 2, &offset_minutes))
-        return NULL;
-    }
-  /* +hhmm or -hhmm */
-  else if (tz_length == 5)
-    {
-      if (!get_iso8601_int (text + i + 1, 2, &offset_hours) ||
-          !get_iso8601_int (text + i + 3, 2, &offset_minutes))
-        return NULL;
-    }
-  /* +hh or -hh */
-  else if (tz_length == 3)
-    {
-      if (!get_iso8601_int (text + i + 1, 2, &offset_hours))
-        return NULL;
-      offset_minutes = 0;
-    }
-  else
-    return NULL;
-
-  *tz_offset = i;
-  tz = g_time_zone_new (text + i);
-
-  /* Double-check that the GTimeZone matches our interpretation of the timezone.
-   * Failure would indicate a bug either here of in the GTimeZone code. */
-  g_assert (g_time_zone_get_offset (tz, 0) == offset_sign * (offset_hours * 3600 + offset_minutes * 60));
-
-  return tz;
-}
-
-static gboolean
-parse_iso8601_time (const gchar *text, gsize length,
-                    gint *hour, gint *minute, gdouble *seconds, GTimeZone **tz)
-{
-  gssize tz_offset = -1;
-
-  /* Check for timezone suffix */
-  *tz = parse_iso8601_timezone (text, length, &tz_offset);
-  if (tz_offset >= 0)
-    length = tz_offset;
-
-  /* hh:mm:ss(.sss) */
-  if (length >= 8 && text[2] == ':' && text[5] == ':')
-    {
-      return get_iso8601_int (text, 2, hour) &&
-             get_iso8601_int (text + 3, 2, minute) &&
-             get_iso8601_seconds (text + 6, length - 6, seconds);
-    }
-  /* hhmmss(.sss) */
-  else if (length >= 6)
-    {
-      return get_iso8601_int (text, 2, hour) &&
-             get_iso8601_int (text + 2, 2, minute) &&
-             get_iso8601_seconds (text + 4, length - 4, seconds);
-    }
-  else
-    return FALSE;
-}
-
-
-GDateTime *
-flatpak_g_date_time_new_from_iso8601 (const gchar *text, GTimeZone *default_tz)
-{
-  gint length, date_length = -1;
-  gint hour = 0, minute = 0;
-  gdouble seconds = 0.0;
-  GTimeZone *tz = NULL;
-  GDateTime *datetime = NULL;
-
-  g_return_val_if_fail (text != NULL, NULL);
-
-  /* Count length of string and find date / time separator ('T', 't', or ' ') */
-  for (length = 0; text[length] != '\0'; length++)
-    {
-      if (date_length < 0 && (text[length] == 'T' || text[length] == 't' || text[length] == ' '))
-        date_length = length;
-    }
-
-  if (date_length < 0)
-    return NULL;
-
-  if (!parse_iso8601_time (text + date_length + 1, length - (date_length + 1),
-                           &hour, &minute, &seconds, &tz))
-    goto out;
-  if (tz == NULL && default_tz == NULL)
-    return NULL;
-
-  datetime = parse_iso8601_date (text, date_length, hour, minute, seconds, tz ? tz : default_tz);
-
-out:
-  if (tz != NULL)
-    g_time_zone_unref (tz);
-  return datetime;
-}
-#endif
-
 /* Convert an app id to a dconf path in the obvious way.
  */
 char *
@@ -9358,65 +8691,3 @@ running_under_sudo (void)
 
   return FALSE;
 }
-
-#if !GLIB_CHECK_VERSION (2, 62, 0)
-void
-g_ptr_array_extend (GPtrArray  *array_to_extend,
-                    GPtrArray  *array,
-                    GCopyFunc   func,
-                    gpointer    user_data)
-{
-  for (gsize i = 0; i < array->len; i++)
-    {
-      if (func)
-        g_ptr_array_add (array_to_extend, func (g_ptr_array_index (array, i), user_data));
-      else
-        g_ptr_array_add (array_to_extend, g_ptr_array_index (array, i));
-    }
-}
-#endif
-
-#if !GLIB_CHECK_VERSION (2, 68, 0)
-/* All this code is backported directly from glib */
-guint
-g_string_replace (GString     *string,
-                  const gchar *find,
-                  const gchar *replace,
-                  guint        limit)
-{
-  gsize f_len, r_len, pos;
-  gchar *cur, *next;
-  guint n = 0;
-
-  g_return_val_if_fail (string != NULL, 0);
-  g_return_val_if_fail (find != NULL, 0);
-  g_return_val_if_fail (replace != NULL, 0);
-
-  f_len = strlen (find);
-  r_len = strlen (replace);
-  cur = string->str;
-
-  while ((next = strstr (cur, find)) != NULL)
-    {
-      pos = next - string->str;
-      g_string_erase (string, pos, f_len);
-      g_string_insert (string, pos, replace);
-      cur = string->str + pos + r_len;
-      n++;
-      /* Only match the empty string once at any given position, to
-       * avoid infinite loops */
-      if (f_len == 0)
-        {
-          if (cur[0] == '\0')
-            break;
-          else
-            cur++;
-        }
-      if (n == limit)
-        break;
-    }
-
-  return n;
-}
-
-#endif /* GLIB_CHECK_VERSION (2, 68, 0) */
diff --git a/common/meson.build b/common/meson.build
index 86d0573c..7c07cf07 100644
--- a/common/meson.build
+++ b/common/meson.build
@@ -139,6 +139,7 @@ sources = [
   'flatpak-dir.c',
   'flatpak-error.c',
   'flatpak-exports.c',
+  'flatpak-glib-backports.c',
   'flatpak-installation.c',
   'flatpak-installed-ref.c',
   'flatpak-instance.c',