getumask: New module.

* lib/sys_stat.in.h (getumask): New declaration.
* lib/getumask.c: New file.
* m4/getumask.m4: New file.
* m4/sys_stat_h.m4 (gl_HEADER_SYS_STAT_H): Test whether getumask is
declared.
(gl_SYS_STAT_H_DEFAULTS): Initialize GNULIB_GETUMASK, HAVE_GETUMASK.
* modules/sys_stat (Makefile.am): Substitute GNULIB_GETUMASK,
HAVE_GETUMASK.
* modules/getumask: New file.
* tests/test-sys_stat-c++.cc (getumask): Check signature.
* doc/glibc-functions/getumask.texi: New file.
* doc/gnulib.texi (Glibc sys/stat.h): Include it.

2 files changed, 29 insertions, 3 deletions

diff --git a/m4/getumask.m4 b/m4/getumask.m4
new file mode 100644
index 0000000000..f8b526d311
--- /dev/null
+++ b/m4/getumask.m4
@@ -0,0 +1,24 @@
+# getumask.m4 serial 1
+dnl Copyright 2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_GETUMASK],
+[
+  AC_REQUIRE([gl_SYS_STAT_H_DEFAULTS])
+
+  dnl Persuade glibc <sys/stat.h> to declare getumask().
+  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
+
+  AC_CHECK_FUNCS_ONCE([getumask])
+  if test $ac_cv_func_getumask = no; then
+    HAVE_GETUMASK=0
+  fi
+])
+
+# Prerequisites of lib/getumask.c.
+AC_DEFUN([gl_PREREQ_GETUMASK],
+[
+  :
+])
diff --git a/m4/sys_stat_h.m4 b/m4/sys_stat_h.m4
index 3efba5a7b9..929144d155 100644
--- a/m4/sys_stat_h.m4
+++ b/m4/sys_stat_h.m4
@@ -1,4 +1,4 @@
-# sys_stat_h.m4 serial 33   -*- Autoconf -*-
+# sys_stat_h.m4 serial 34   -*- Autoconf -*-
 dnl Copyright (C) 2006-2020 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -46,8 +46,8 @@ AC_DEFUN([gl_HEADER_SYS_STAT_H],
   dnl Check for declarations of anything we want to poison if the
   dnl corresponding gnulib module is not in use.
   gl_WARN_ON_USE_PREPARE([[#include <sys/stat.h>
-    ]], [fchmodat fstat fstatat futimens lchmod lstat mkdirat mkfifo mkfifoat
-    mknod mknodat stat utimensat])
+    ]], [fchmodat fstat fstatat futimens getumask lchmod lstat
+    mkdirat mkfifo mkfifoat mknod mknodat stat utimensat])
 
   AC_REQUIRE([AC_C_RESTRICT])
 ])
@@ -68,6 +68,7 @@ AC_DEFUN([gl_SYS_STAT_H_DEFAULTS],
   GNULIB_FSTAT=0;       AC_SUBST([GNULIB_FSTAT])
   GNULIB_FSTATAT=0;     AC_SUBST([GNULIB_FSTATAT])
   GNULIB_FUTIMENS=0;    AC_SUBST([GNULIB_FUTIMENS])
+  GNULIB_GETUMASK=0;    AC_SUBST([GNULIB_GETUMASK])
   GNULIB_LCHMOD=0;      AC_SUBST([GNULIB_LCHMOD])
   GNULIB_LSTAT=0;       AC_SUBST([GNULIB_LSTAT])
   GNULIB_MKDIRAT=0;     AC_SUBST([GNULIB_MKDIRAT])
@@ -82,6 +83,7 @@ AC_DEFUN([gl_SYS_STAT_H_DEFAULTS],
   HAVE_FCHMODAT=1;      AC_SUBST([HAVE_FCHMODAT])
   HAVE_FSTATAT=1;       AC_SUBST([HAVE_FSTATAT])
   HAVE_FUTIMENS=1;      AC_SUBST([HAVE_FUTIMENS])
+  HAVE_GETUMASK=1;      AC_SUBST([HAVE_GETUMASK])
   HAVE_LCHMOD=1;        AC_SUBST([HAVE_LCHMOD])
   HAVE_LSTAT=1;         AC_SUBST([HAVE_LSTAT])
   HAVE_MKDIRAT=1;       AC_SUBST([HAVE_MKDIRAT])