build: Fix the set of exported symbols on Alpine Linux.

* build-aux/join-v-1: New file.
* Makefile.am (EXTRA_DIST): Add it.
* lib/Makefile.am (config.h): Use it instead of 'join -v 1'.

4 files changed, 54 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index e94815e..c807132 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2021-04-06  Bruno Haible  <bruno@clisp.org>
+
+	build: Fix the set of exported symbols on Alpine Linux.
+	* build-aux/join-v-1: New file.
+	* Makefile.am (EXTRA_DIST): Add it.
+	* lib/Makefile.am (config.h): Use it instead of 'join -v 1'.
+
 2021-02-28  Bruno Haible  <bruno@clisp.org>
 
 	Update DEPENDENCIES.
diff --git a/Makefile.am b/Makefile.am
index fdc3e68..2fdb9c2 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,5 +1,5 @@
 ## Makefile for the toplevel directory of GNU libunistring.
-## Copyright (C) 2009, 2016, 2018 Free Software Foundation, Inc.
+## Copyright (C) 2009, 2016, 2018, 2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
@@ -23,7 +23,7 @@ SUBDIRS = doc gnulib-local lib tests
 
 EXTRA_DIST = \
   version.sh BUGS DEPENDENCIES HACKING autogen.sh \
-  build-aux/texi2html build-aux/run-test
+  build-aux/join-v-1 build-aux/texi2html build-aux/run-test
 
 
 # Allow users to use "gnulib-tool --update".
diff --git a/build-aux/join-v-1 b/build-aux/join-v-1
new file mode 100755
index 0000000..d1948ac
--- /dev/null
+++ b/build-aux/join-v-1
@@ -0,0 +1,43 @@
+#!/bin/sh
+# join-v-1 - Filter out a set of items from another set of items.
+
+# Copyright (C) 2021 Free Software Foundation, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+# Usage: join-v-1 FILE1 FILE2
+# Produces on stdout a list of items that are contained in FILE1 but not
+# contained in FILE2.  The items are strings without whitespace.
+# FILE1 and FILE2 contain such items, one per line, sorted according to
+# the current locale.
+# FILE1 or FILE2 can be specified as '-', which denotes standard input.
+
+# The 'join' program does not exist on all platforms.  Where it exists,
+# we can use it.
+if (type join) >/dev/null 2>&1; then
+  join -v 1 "$1" "$2"
+else
+  # Two solutions based on awk, by Bernhard Voelker <mail@bernhard-voelker.de>.
+  if true; then
+    awk -v keyfile="$2" '
+      BEGIN { while ((getline < keyfile) > 0) k[$1]=1 }
+      !k[$1]
+      ' "$1"
+  else
+    awk '
+      keys { k[$1]=1; next }
+      !k[$1]
+      ' keys=1 "$2" keys=0 "$1"
+  fi
+fi
diff --git a/lib/Makefile.am b/lib/Makefile.am
index 6136ced..3ed6230 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -1,5 +1,5 @@
 ## Makefile for the lib subdirectory of GNU libunistring.
-## Copyright (C) 2009-2019 Free Software Foundation, Inc.
+## Copyright (C) 2009-2021 Free Software Foundation, Inc.
 ##
 ## This program is free software: you can redistribute it and/or modify
 ## it under the terms of the GNU General Public License as published by
@@ -303,7 +303,7 @@ config.h: $(BUILT_SOURCES) $(srcdir)/libunistring.sym
 	      done; \
 	    } 5>&1 1>&2 \
 	      | sed -e 's,.* ,,' | grep -v '@' | LC_ALL=C sort | LC_ALL=C uniq \
-	      | LC_ALL=C join -v 1 - $(srcdir)/libunistring.sym \
+	      | LC_ALL=C $(top_srcdir)/build-aux/join-v-1 - $(srcdir)/libunistring.sym \
 	      | grep -v '^libintl_locale' \
 	      | grep -v 'gl_get_setlocale_null_lock' \
 	      | sed -e 's,^\(.*\)$$,#define \1 libunistring_\1,' > config.h-t; \