+m4_version_prereq([2.70], [] ,[
+
+# This is adapted with modifications from upstream Autoconf here:
+# https://git.savannah.gnu.org/cgit/autoconf.git/commit/?id=04be2b7a29d65d9a08e64e8e56e594c91749598c
+AC_DEFUN([_AC_FUNC_MALLOC_IF],
+[
+ AC_REQUIRE([AC_HEADER_STDC])dnl
+ AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
+ AC_CHECK_HEADERS([stdlib.h])
+ AC_CACHE_CHECK([for GNU libc compatible malloc],
+ [ac_cv_func_malloc_0_nonnull],
+ [AC_RUN_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#if defined STDC_HEADERS || defined HAVE_STDLIB_H
+ # include <stdlib.h>
+ #else
+ char *malloc ();
+ #endif
+ ]],
+ [[char *p = malloc (0);
+ int result = !p;
+ free (p);
+ return result;]])
+ ],
+ [ac_cv_func_malloc_0_nonnull=yes],
+ [ac_cv_func_malloc_0_nonnull=no],
+ [case "$host_os" in
+ # Guess yes on platforms where we know the result.
+ *-gnu* | gnu* | freebsd* | netbsd* | openbsd* \
+ | hpux* | solaris* | cygwin* | mingw*)
+ ac_cv_func_malloc_0_nonnull=yes ;;
+ # If we don't know, assume the worst.
+ *) ac_cv_func_malloc_0_nonnull=no ;;
+ esac
+ ])
+ ])
+ AS_IF([test $ac_cv_func_malloc_0_nonnull = yes], [$1], [$2])
+])# _AC_FUNC_MALLOC_IF
+
+])
+
+# gl_FUNC_MALLOC_GNU
+# ------------------
+# Test whether 'malloc (0)' is handled like in GNU libc, and replace malloc if
+# it is not.
+AC_DEFUN([gl_FUNC_MALLOC_GNU],
+[
+ AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+ dnl _AC_FUNC_MALLOC_IF is defined in Autoconf.
+ _AC_FUNC_MALLOC_IF(
+ [AC_DEFINE([HAVE_MALLOC_GNU], [1],
+ [Define to 1 if your system has a GNU libc compatible 'malloc'
+ function, and to 0 otherwise.])],
+ [AC_DEFINE([HAVE_MALLOC_GNU], [0])
+ REPLACE_MALLOC=1
+ ])
+])
+