1 files changed, 93 insertions, 0 deletions
diff --git a/m4/calloc.m4 b/m4/calloc.m4
new file mode 100644
index 0000000..2e0d8ff
--- /dev/null
+++ b/m4/calloc.m4
@@ -0,0 +1,93 @@
+# calloc.m4 serial 20
+
+# Copyright (C) 2004-2020 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Written by Jim Meyering.
+
+# Determine whether calloc (N, S) returns non-NULL when N*S is zero,
+# and returns NULL when N*S overflows.
+# If so, define HAVE_CALLOC.  Otherwise, define calloc to rpl_calloc
+# and arrange to use a calloc wrapper function that does work in that case.
+
+# _AC_FUNC_CALLOC_IF([IF-WORKS], [IF-NOT])
+# -------------------------------------
+# If 'calloc (0, 0)' is properly handled, run IF-WORKS, otherwise, IF-NOT.
+AC_DEFUN([_AC_FUNC_CALLOC_IF],
+[
+  AC_REQUIRE([AC_TYPE_SIZE_T])dnl
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  AC_CACHE_CHECK([for GNU libc compatible calloc],
+    [ac_cv_func_calloc_0_nonnull],
+    [AC_RUN_IFELSE(
+       [AC_LANG_PROGRAM(
+          [AC_INCLUDES_DEFAULT],
+          [[int result = 0;
+            char *p = calloc (0, 0);
+            if (!p)
+              result |= 1;
+            free (p);
+            p = calloc ((size_t) -1 / 8 + 1, 8);
+            if (p)
+              result |= 2;
+            free (p);
+            return result;
+          ]])],
+       [ac_cv_func_calloc_0_nonnull=yes],
+       [ac_cv_func_calloc_0_nonnull=no],
+       [case "$host_os" in
+                         # Guess yes on glibc systems.
+          *-gnu* | gnu*) ac_cv_func_calloc_0_nonnull="guessing yes" ;;
+                         # Guess yes on musl systems.
+          *-musl*)       ac_cv_func_calloc_0_nonnull="guessing yes" ;;
+                         # Guess yes on native Windows.
+          mingw*)        ac_cv_func_calloc_0_nonnull="guessing yes" ;;
+                         # If we don't know, obey --enable-cross-guesses.
+          *)             ac_cv_func_calloc_0_nonnull="$gl_cross_guess_normal" ;;
+        esac
+       ])])
+  case "$ac_cv_func_calloc_0_nonnull" in
+    *yes)
+      $1
+      ;;
+    *)
+      $2
+      ;;
+  esac
+])# AC_FUNC_CALLOC
+
+
+# gl_FUNC_CALLOC_GNU
+# ------------------
+# Report whether 'calloc (0, 0)' is properly handled, and replace calloc if
+# needed.
+AC_DEFUN([gl_FUNC_CALLOC_GNU],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  _AC_FUNC_CALLOC_IF(
+    [AC_DEFINE([HAVE_CALLOC_GNU], [1],
+               [Define to 1 if your system has a GNU libc compatible 'calloc'
+                function, and to 0 otherwise.])],
+    [AC_DEFINE([HAVE_CALLOC_GNU], [0])
+     REPLACE_CALLOC=1
+    ])
+])# gl_FUNC_CALLOC_GNU
+
+
+# gl_FUNC_CALLOC_POSIX
+# --------------------
+# Test whether 'calloc' is POSIX compliant (sets errno to ENOMEM when it
+# fails), and replace calloc if it is not.
+AC_DEFUN([gl_FUNC_CALLOC_POSIX],
+[
+  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
+  AC_REQUIRE([gl_CHECK_MALLOC_POSIX])
+  if test $gl_cv_func_malloc_posix = yes; then
+    AC_DEFINE([HAVE_CALLOC_POSIX], [1],
+      [Define if the 'calloc' function is POSIX compliant.])
+  else
+    REPLACE_CALLOC=1
+  fi
+])