1 files changed, 26 insertions, 0 deletions

diff --git a/gl/m4/sys_cdefs_h.m4 b/gl/m4/sys_cdefs_h.m4
new file mode 100644
index 00000000..d72796ca
--- /dev/null
+++ b/gl/m4/sys_cdefs_h.m4
@@ -0,0 +1,26 @@
+# sys_cdefs_h.m4 - Is <sys/cdefs.h> compatible enough with glibc?
+# serial 2
+dnl Copyright 2024-2025 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.
+dnl This file is offered as-is, without any warranty.
+
+dnl Written by Paul Eggert.
+
+AC_DEFUN_ONCE([gl_CHECK_HEADER_SYS_CDEFS_H],
+  [AC_CACHE_CHECK([for glibc-compatible sys/cdefs.h],
+     [gl_cv_header_sys_cdefs_h],
+     [AC_COMPILE_IFELSE(
+        [AC_LANG_DEFINES_PROVIDED
+         [#include <sys/cdefs.h>
+          enum { foo = __GNUC_PREREQ (14, 1) } bar;
+        ]],
+        [gl_cv_header_sys_cdefs_h=yes],
+        [gl_cv_header_sys_cdefs_h=no])])
+   if test "$gl_cv_header_sys_cdefs_h" = yes; then
+     HAVE_SYS_CDEFS_H=1
+   else
+     HAVE_SYS_CDEFS_H=0
+   fi
+   AC_SUBST([HAVE_SYS_CDEFS_H])])