Added autoconf patches and fixes

Makefile.am

@@ -48,7 +48,7 @@ pkgconfig_DATA = libmicrohttpd.pc
 EXTRA_DIST += pre-dist-hook-dummy
 MOSTLYCLEANFILES = pre-dist-hook-dummy
 DISTCLEANFILES = 
-MAINTAINERCLEANFILES = 
+MAINTAINERCLEANFILES = m4/c_backported.m4
 
 pre-dist-hook-dummy: pre-dist-hook Makefile
 	@echo "dummy" > $@
@@ -57,6 +57,15 @@ dist-hook: dist-po
 	@chmod u+w '$(distdir)/pre-dist-hook-dummy' && \
 	  rm -f '$(distdir)/pre-dist-hook-dummy'
 	@rm -f pre-dist-hook-dummy
+	@if test -w '$(distdir)/m4/c_backported.m4'; then \
+	  echo "Use empty m4/c_backported.m4 for dist target"; \
+	  touch -r '$(distdir)/m4/c_backported.m4' '$(distdir)/m4/c_backported.m4-tmst' && \
+	    echo '# Not used for distribution' > '$(distdir)/m4/c_backported.m4' && \
+	    touch -r '$(distdir)/m4/c_backported.m4-tmst' '$(distdir)/m4/c_backported.m4' && \
+	    rm -f '$(distdir)/m4/c_backported.m4-tmst'; \
+	else \
+	  true; \
+	fi
 
 pre-dist-hook: pre-dist-hook-doc
 	@echo "Preparing to make dist"

contrib/fixes-autoconf/apply-all.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+
+#
+# This file applies optional Autoconf patches for better MSys2 and new
+# compiler compatibility.
+#
+# Based on Debian SID baseline files as of April 2023.
+#
+
+patchesdir=$(dirname $BASH_SOURCE) || exit 2
+test -n "$patchesdir" || exit 2
+cd "$patchesdir" || exit 2
+patchesdir=$(pwd) || exit 2
+
+patches=(
+ # No patches currently
+)
+
+failed=( )
+
+cd "${patchesdir}/../.." || exit 1
+
+patch_params="-Nf -p1 --no-backup-if-mismatch -r - --read-only=fail"
+
+for patch in ${patches[@]}; do
+  patchfile="${patchesdir}/${patch}"
+  echo "*** Applying $patch..."
+  if echo "$patch_data" | patch $patch_params -i "$patchfile"
+  then
+    echo "** $patch successfully applied."
+  else
+    echo "** $patch failed."
+    failed+=("$patch")
+  fi
+  unset patch_data
+done
+
+
+addl_file="c_backported.m4"
+echo "*** Copying $addl_file"
+cp -fT "${patchesdir}/$addl_file" "m4/$addl_file" || exit 2
+echo "$addl_file copied."
+
+echo ''
+
+if [[ -n "${failed[@]}" ]]; then
+  printf '* Failed patch: %s\n' "${failed[@]}" >&2
+  exit 2
+else
+  echo "* All patches have been successfully applied."
+fi
+
+exit 0

contrib/fixes-autoconf/c_backported.m4

@@ -0,0 +1,565 @@
+# Backported macros from autoconf git master + a few custom patches
+
+# This file is part of Autoconf.			-*- Autoconf -*-
+# Programming languages support.
+# Copyright (C) 2001-2017, 2020-2023 Free Software Foundation, Inc.
+
+# This file is part of Autoconf.  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.
+#
+# Under Section 7 of GPL version 3, you are granted additional
+# permissions described in the Autoconf Configure Script Exception,
+# version 3.0, as published by the Free Software Foundation.
+#
+# You should have received a copy of the GNU General Public License
+# and a copy of the Autoconf Configure Script Exception along with
+# this program; see the files COPYINGv3 and COPYING.EXCEPTION
+# respectively.  If not, see <https://www.gnu.org/licenses/>.
+
+# Written by David MacKenzie, with help from
+# Akim Demaille, Paul Eggert,
+# François Pinard, Karl Berry, Richard Pixley, Ian Lance Taylor,
+# Roland McGrath, Noah Friedman, david d zuhn, and many others.
+
+# ---- Backported macros only ----
+
+AC_DEFUN([_AC_C_C89_TEST_GLOBALS],
+[m4_divert_text([INIT_PREPARE],
+[[# Test code for whether the C compiler supports C89 (global declarations)
+ac_c_conftest_c89_globals='
+/* Does the compiler advertise C89 conformance?
+   Do not test the value of __STDC__, because some compilers set it to 0
+   while being otherwise adequately conformant. */
+#if !defined __STDC__
+# error "Compiler does not advertise C89 conformance"
+#endif
+
+#include <stddef.h>
+#include <stdarg.h>
+struct stat;
+/* Most of the following tests are stolen from RCS 5.7 src/conf.sh.  */
+struct buf { int x; };
+struct buf * (*rcsopen) (struct buf *, struct stat *, int);
+static char *e (char **p, int i)
+{
+  return p[i];
+}
+static char *f (char * (*g) (char **, int), char **p, ...)
+{
+  char *s;
+  va_list v;
+  va_start (v,p);
+  s = g (p, va_arg (v,int));
+  va_end (v);
+  return s;
+}
+
+/* C89 style stringification. */
+#define noexpand_stringify(a) #a
+const char *stringified = noexpand_stringify(arbitrary+token=sequence);
+
+/* C89 style token pasting.  Exercises some of the corner cases that
+   e.g. old MSVC gets wrong, but not very hard. */
+#define noexpand_concat(a,b) a##b
+#define expand_concat(a,b) noexpand_concat(a,b)
+extern int vA;
+extern int vbee;
+#define aye A
+#define bee B
+int *pvA = &expand_concat(v,aye);
+int *pvbee = &noexpand_concat(v,bee);
+
+/* OSF 4.0 Compaq cc is some sort of almost-ANSI by default.  It has
+   function prototypes and stuff, but not \xHH hex character constants.
+   These do not provoke an error unfortunately, instead are silently treated
+   as an "x".  The following induces an error, until -std is added to get
+   proper ANSI mode.  Curiously \x00 != x always comes out true, for an
+   array size at least.  It is necessary to write \x00 == 0 to get something
+   that is true only with -std.  */
+int osf4_cc_array ['\''\x00'\'' == 0 ? 1 : -1];
+
+/* IBM C 6 for AIX is almost-ANSI by default, but it replaces macro parameters
+   inside strings and character constants.  */
+#define FOO(x) '\''x'\''
+int xlc6_cc_array[FOO(a) == '\''x'\'' ? 1 : -1];
+
+int test (int i, double x);
+struct s1 {int (*f) (int a);};
+struct s2 {int (*f) (double a);};
+int pairnames (int, char **, int *(*)(struct buf *, struct stat *, int),
+               int, int);'
+]])])
+
+
+AC_DEFUN([_AC_C_C99_TEST_GLOBALS],
+[m4_divert_text([INIT_PREPARE],
+[[# Test code for whether the C compiler supports C99 (global declarations)
+ac_c_conftest_c99_globals='
+// Does the compiler advertise C99 conformance?
+#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 199901L
+# error "Compiler does not advertise C99 conformance"
+#endif
+
+#include <stdbool.h>
+extern int puts (const char *);
+extern int printf (const char *, ...);
+extern int dprintf (int, const char *, ...);
+extern void *malloc (size_t);
+extern void free (void *);
+
+// Check varargs macros.  These examples are taken from C99 6.10.3.5.
+// dprintf is used instead of fprintf to avoid needing to declare
+// FILE and stderr.
+#define debug(...) dprintf (2, __VA_ARGS__)
+#define showlist(...) puts (#__VA_ARGS__)
+#define report(test,...) ((test) ? puts (#test) : printf (__VA_ARGS__))
+static void
+test_varargs_macros (void)
+{
+  int x = 1234;
+  int y = 5678;
+  debug ("Flag");
+  debug ("X = %d\n", x);
+  showlist (The first, second, and third items.);
+  report (x>y, "x is %d but y is %d", x, y);
+}
+
+// Check long long types.
+#define BIG64 18446744073709551615ull
+#define BIG32 4294967295ul
+#define BIG_OK (BIG64 / BIG32 == 4294967297ull && BIG64 % BIG32 == 0)
+#if !BIG_OK
+  #error "your preprocessor is broken"
+#endif
+#if BIG_OK
+#else
+  #error "your preprocessor is broken"
+#endif
+static long long int bignum = -9223372036854775807LL;
+static unsigned long long int ubignum = BIG64;
+
+struct incomplete_array
+{
+  int datasize;
+  double data[];
+};
+
+struct named_init {
+  int number;
+  const wchar_t *name;
+  double average;
+};
+
+typedef const char *ccp;
+
+static inline int
+test_restrict (ccp restrict text)
+{
+  // See if C++-style comments work.
+  // Iterate through items via the restricted pointer.
+  // Also check for declarations in for loops.
+  for (unsigned int i = 0; *(text+i) != '\''\0'\''; ++i)
+    continue;
+  return 0;
+}
+
+// Check varargs and va_copy.
+static bool
+test_varargs (const char *format, ...)
+{
+  va_list args;
+  va_start (args, format);
+  va_list args_copy;
+  va_copy (args_copy, args);
+
+  const char *str = "";
+  int number = 0;
+  float fnumber = 0;
+
+  while (*format)
+    {
+      switch (*format++)
+	{
+	case '\''s'\'': // string
+	  str = va_arg (args_copy, const char *);
+	  break;
+	case '\''d'\'': // int
+	  number = va_arg (args_copy, int);
+	  break;
+	case '\''f'\'': // float
+	  fnumber = va_arg (args_copy, double);
+	  break;
+	default:
+	  break;
+	}
+    }
+  va_end (args_copy);
+  va_end (args);
+
+  return *str && number && fnumber;
+}
+'
+]])])
+
+
+AC_DEFUN([_AC_C_C11_TEST_GLOBALS],
+[m4_divert_text([INIT_PREPARE],
+[[# Test code for whether the C compiler supports C11 (global declarations)
+ac_c_conftest_c11_globals='
+// Does the compiler advertise C11 conformance?
+#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112L
+# error "Compiler does not advertise C11 conformance"
+#endif
+
+// Check _Alignas.
+char _Alignas (double) aligned_as_double;
+char _Alignas (0) no_special_alignment;
+extern char aligned_as_int;
+char _Alignas (0) _Alignas (int) aligned_as_int;
+
+// Check _Alignof.
+enum
+{
+  int_alignment = _Alignof (int),
+  int_array_alignment = _Alignof (int[100]),
+  char_alignment = _Alignof (char)
+};
+_Static_assert (0 < -_Alignof (int), "_Alignof is signed");
+
+// Check _Noreturn.
+_Noreturn int does_not_return (void) { for (;;) continue; }
+
+// Check _Static_assert.
+struct test_static_assert
+{
+  int x;
+  _Static_assert (sizeof (int) <= sizeof (long int),
+                  "_Static_assert does not work in struct");
+  long int y;
+};
+
+// Check UTF-8 literals.
+#define u8 syntax error!
+char const utf8_literal[] = u8"happens to be ASCII" "another string";
+
+// Check duplicate typedefs.
+typedef long *long_ptr;
+typedef long int *long_ptr;
+typedef long_ptr long_ptr;
+
+// Anonymous structures and unions -- taken from C11 6.7.2.1 Example 1.
+struct anonymous
+{
+  union {
+    struct { int i; int j; };
+    struct { int k; long int l; } w;
+  };
+  int m;
+} v1;
+'
+]])])
+
+
+# AC_LANG_CALL(C)(PROLOGUE, FUNCTION)
+# -----------------------------------
+# Avoid conflicting decl of main.
+m4_define([AC_LANG_CALL(C)],
+[AC_LANG_PROGRAM([$1
+m4_if([$2], [main], ,
+[/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.
+   The 'extern "C"' is for builds by C++ compilers;
+   although this is not generally supported in C code supporting it here
+   has little cost and some practical benefit (sr 110532).  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char $2 (void);])], [return $2 ();])])
+
+
+# AC_LANG_FUNC_LINK_TRY(C)(FUNCTION)
+# ----------------------------------
+# Don't include <ctype.h> because on OSF/1 3.0 it includes
+# <sys/types.h> which includes <sys/select.h> which contains a
+# prototype for select.  Similarly for bzero.
+#
+# This test used to merely assign f=$1 in main(), but that was
+# optimized away by HP unbundled cc A.05.36 for ia64 under +O3,
+# presumably on the basis that there's no need to do that store if the
+# program is about to exit.  Conversely, the AIX linker optimizes an
+# unused external declaration that initializes f=$1.  So this test
+# program has both an external initialization of f, and a use of f in
+# main that affects the exit status.
+#
+m4_define([AC_LANG_FUNC_LINK_TRY(C)],
+[AC_LANG_PROGRAM(
+[/* Define $1 to an innocuous variant, in case <limits.h> declares $1.
+   For example, HP-UX 11i <limits.h> declares gettimeofday.  */
+#define $1 innocuous_$1
+
+/* System header to define __stub macros and hopefully few prototypes,
+   which can conflict with char $1 (void); below.  */
+
+#include <limits.h>
+#undef $1
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char $1 (void);
+/* The GNU C library defines this for functions which it implements
+    to always fail with ENOSYS.  Some functions are actually named
+    something starting with __ and the normal name is an alias.  */
+#if defined __stub_$1 || defined __stub___$1
+choke me
+#endif
+], [return $1 ();])])
+
+
+# AC_C_BIGENDIAN ([ACTION-IF-TRUE], [ACTION-IF-FALSE], [ACTION-IF-UNKNOWN],
+#                 [ACTION-IF-UNIVERSAL])
+# -------------------------------------------------------------------------
+AC_DEFUN([AC_C_BIGENDIAN],
+[AH_VERBATIM([WORDS_BIGENDIAN],
+[/* Define WORDS_BIGENDIAN to 1 if your processor stores words with the most
+   significant byte first (like Motorola and SPARC, unlike Intel). */
+#if defined AC_APPLE_UNIVERSAL_BUILD
+# if defined __BIG_ENDIAN__
+#  define WORDS_BIGENDIAN 1
+# endif
+#else
+# ifndef WORDS_BIGENDIAN
+#  undef WORDS_BIGENDIAN
+# endif
+#endif])dnl
+ AC_CACHE_CHECK([whether byte ordering is bigendian], [ac_cv_c_bigendian],
+   [ac_cv_c_bigendian=unknown
+    # See if we're dealing with a universal compiler.
+    AC_COMPILE_IFELSE(
+	 [AC_LANG_SOURCE(
+	    [[#ifndef __APPLE_CC__
+	       not a universal capable compiler
+	     #endif
+	     typedef int dummy;
+	    ]])],
+	 [
+	# Check for potential -arch flags.  It is not universal unless
+	# there are at least two -arch flags with different values.
+	ac_arch=
+	ac_prev=
+	for ac_word in $CC $CFLAGS $CPPFLAGS $LDFLAGS; do
+	 if test -n "$ac_prev"; then
+	   case $ac_word in
+	     i?86 | x86_64 | ppc | ppc64)
+	       if test -z "$ac_arch" || test "$ac_arch" = "$ac_word"; then
+		 ac_arch=$ac_word
+	       else
+		 ac_cv_c_bigendian=universal
+		 break
+	       fi
+	       ;;
+	   esac
+	   ac_prev=
+	 elif test "x$ac_word" = "x-arch"; then
+	   ac_prev=arch
+	 fi
+       done])
+    if test $ac_cv_c_bigendian = unknown; then
+      # See if sys/param.h defines the BYTE_ORDER macro.
+      AC_COMPILE_IFELSE(
+	[AC_LANG_PROGRAM(
+	   [[#include <sys/types.h>
+	     #include <sys/param.h>
+	   ]],
+	   [[#if ! (defined BYTE_ORDER && defined BIG_ENDIAN \\
+		     && defined LITTLE_ENDIAN && BYTE_ORDER && BIG_ENDIAN \\
+		     && LITTLE_ENDIAN)
+	      bogus endian macros
+	     #endif
+	   ]])],
+	[# It does; now see whether it defined to BIG_ENDIAN or not.
+	 AC_COMPILE_IFELSE(
+	   [AC_LANG_PROGRAM(
+	      [[#include <sys/types.h>
+		#include <sys/param.h>
+	      ]],
+	      [[#if BYTE_ORDER != BIG_ENDIAN
+		 not big endian
+		#endif
+	      ]])],
+	   [ac_cv_c_bigendian=yes],
+	   [ac_cv_c_bigendian=no])])
+    fi
+    if test $ac_cv_c_bigendian = unknown; then
+      # See if <limits.h> defines _LITTLE_ENDIAN or _BIG_ENDIAN (e.g., Solaris).
+      AC_COMPILE_IFELSE(
+	[AC_LANG_PROGRAM(
+	   [[#include <limits.h>
+	   ]],
+	   [[#if ! (defined _LITTLE_ENDIAN || defined _BIG_ENDIAN)
+	      bogus endian macros
+	     #endif
+	   ]])],
+	[# It does; now see whether it defined to _BIG_ENDIAN or not.
+	 AC_COMPILE_IFELSE(
+	   [AC_LANG_PROGRAM(
+	      [[#include <limits.h>
+	      ]],
+	      [[#ifndef _BIG_ENDIAN
+		 not big endian
+		#endif
+	      ]])],
+	   [ac_cv_c_bigendian=yes],
+	   [ac_cv_c_bigendian=no])])
+    fi
+    if test $ac_cv_c_bigendian = unknown; then
+      # Compile a test program.
+      AC_RUN_IFELSE(
+	[AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],
+	   [[
+	     /* Are we little or big endian?  From Harbison&Steele.  */
+	     union
+	     {
+	       long int l;
+	       char c[sizeof (long int)];
+	     } u;
+	     u.l = 1;
+	     return u.c[sizeof (long int) - 1] == 1;
+	   ]])],
+	[ac_cv_c_bigendian=no],
+	[ac_cv_c_bigendian=yes],
+	[# Try to guess by grepping values from an object file.
+	 AC_LINK_IFELSE(
+	   [AC_LANG_SOURCE(
+	      [[unsigned short int ascii_mm[] =
+		  { 0x4249, 0x4765, 0x6E44, 0x6961, 0x6E53, 0x7953, 0 };
+		unsigned short int ascii_ii[] =
+		  { 0x694C, 0x5454, 0x656C, 0x6E45, 0x6944, 0x6E61, 0 };
+		int use_ascii (int i) {
+		  return ascii_mm[i] + ascii_ii[i];
+		}
+		unsigned short int ebcdic_ii[] =
+		  { 0x89D3, 0xE3E3, 0x8593, 0x95C5, 0x89C4, 0x9581, 0 };
+		unsigned short int ebcdic_mm[] =
+		  { 0xC2C9, 0xC785, 0x95C4, 0x8981, 0x95E2, 0xA8E2, 0 };
+		int use_ebcdic (int i) {
+		  return ebcdic_mm[i] + ebcdic_ii[i];
+		}
+		int
+		main (int argc, char **argv)
+		{
+		  /* Intimidate the compiler so that it does not
+		     optimize the arrays away.  */
+		  char *p = argv[0];
+		  ascii_mm[1] = *p++; ebcdic_mm[1] = *p++;
+		  ascii_ii[1] = *p++; ebcdic_ii[1] = *p++;
+		  return use_ascii (argc) == use_ebcdic (*p);
+		}]])],
+	   [if grep BIGenDianSyS conftest$ac_exeext >/dev/null; then
+	      ac_cv_c_bigendian=yes
+	    fi
+	    if grep LiTTleEnDian conftest$ac_exeext >/dev/null ; then
+	      if test "$ac_cv_c_bigendian" = unknown; then
+		ac_cv_c_bigendian=no
+	      else
+		# finding both strings is unlikely to happen, but who knows?
+		ac_cv_c_bigendian=unknown
+	      fi
+	    fi])])
+    fi])
+ case $ac_cv_c_bigendian in #(
+   yes)
+     m4_default([$1],
+       [AC_DEFINE([WORDS_BIGENDIAN], 1)]);; #(
+   no)
+     $2 ;; #(
+   universal)
+dnl Note that AC_APPLE_UNIVERSAL_BUILD sorts less than WORDS_BIGENDIAN;
+dnl this is a necessity for proper config header operation.  Warn if
+dnl the user did not specify a config header but is relying on the
+dnl default behavior for universal builds.
+     m4_default([$4],
+       [AC_CONFIG_COMMANDS_PRE([m4_ifset([AH_HEADER], [],
+	 [m4_warn([obsolete],
+	   [AC_C_BIGENDIAN should be used with AC_CONFIG_HEADERS])])])dnl
+	AC_DEFINE([AC_APPLE_UNIVERSAL_BUILD],1,
+	  [Define if building universal (internal helper macro)])])
+     ;; #(
+   *)
+     m4_default([$3],
+       [AC_MSG_ERROR([unknown endianness
+ presetting ac_cv_c_bigendian=no (or yes) will help])]) ;;
+ esac
+])# AC_C_BIGENDIAN
+
+
+# AC_C_VARARRAYS
+# --------------
+# Check whether the C compiler supports variable-length arrays.
+AC_DEFUN([AC_C_VARARRAYS],
+[
+  AC_CACHE_CHECK([for variable-length arrays],
+    ac_cv_c_vararrays,
+    [AC_COMPILE_IFELSE([AC_LANG_SOURCE(
+[[	#ifndef __STDC_NO_VLA__
+	#error __STDC_NO_VLA__ not defined
+	#endif
+]])],
+       [ac_cv_c_vararrays='no: __STDC_NO_VLA__ is defined'],
+       [AC_COMPILE_IFELSE(
+	  [AC_LANG_PROGRAM(
+	     [[/* Test for VLA support.  This test is partly inspired
+		  from examples in the C standard.  Use at least two VLA
+		  functions to detect the GCC 3.4.3 bug described in:
+		  https://lists.gnu.org/archive/html/bug-gnulib/2014-08/msg00014.html
+		  */
+	       #ifdef __STDC_NO_VLA__
+		syntax error;
+	       #else
+		 extern int n;
+		 static int B[100];
+		 int fvla (int m, int C[m][m]);
+
+		 static int
+		 simple (int count, int all[static count])
+		 {
+		   return all[count - 1];
+		 }
+
+		 int
+		 fvla (int m, int C[m][m])
+		 {
+		   typedef int VLA[m][m];
+		   VLA x;
+		   int D[m];
+		   static int (*q)[m] = &B;
+		   int (*s)[n] = q;
+		   return C && &x[0][0] == &D[0] && &D[0] == s[0];
+		 }
+	       #endif
+	       ]])],
+	  [ac_cv_c_vararrays=yes],
+	  [ac_cv_c_vararrays=no])])])
+  if test "$ac_cv_c_vararrays" = yes; then
+    dnl This is for compatibility with Autoconf 2.61-2.69.
+    AC_DEFINE([HAVE_C_VARARRAYS], 1,
+      [Define to 1 if C supports variable-length arrays.])
+  elif test "$ac_cv_c_vararrays" = no; then
+    AC_DEFINE([__STDC_NO_VLA__], 1,
+      [Define to 1 if C does not support variable-length arrays, and
+       if the compiler does not already define this.])
+  fi
+])
+

m4/.gitignore

@@ -3,3 +3,4 @@
 /ltsugar.m4
 /ltoptions.m4
 /libtool.m4
+/c_backported.m4