--- /dev/null
+--- /dev/null
++++ b/acinclude.m4
+@@ -0,0 +1,109 @@
++dnl ##
++dnl ## Check for C99 va_copy() implementation
++dnl ## (and provide fallback implementation if neccessary)
++dnl ##
++dnl ## configure.in:
++dnl ## AC_CHECK_VA_COPY
++dnl ## foo.c:
++dnl ## #include "config.h"
++dnl ## [...]
++dnl ## va_copy(d,s)
++dnl ##
++dnl ## This check is rather complex: first because we really have to
++dnl ## try various possible implementations in sequence and second, we
++dnl ## cannot define a macro in config.h with parameters directly.
++dnl ##
++
++dnl # test program for va_copy() implementation
++changequote(<<,>>)
++m4_define(__va_copy_test, <<[
++#include <stdlib.h>
++#include <stdarg.h>
++#include <string.h>
++#define DO_VA_COPY(d, s) $1
++void test(char *str, ...)
++{
++ va_list ap, ap2;
++ int i;
++ va_start(ap, str);
++ DO_VA_COPY(ap2, ap);
++ for (i = 1; i <= 9; i++) {
++ int k = (int)va_arg(ap, int);
++ if (k != i)
++ abort();
++ }
++ DO_VA_COPY(ap, ap2);
++ for (i = 1; i <= 9; i++) {
++ int k = (int)va_arg(ap, int);
++ if (k != i)
++ abort();
++ }
++ va_end(ap);
++}
++int main(int argc, char *argv[])
++{
++ test("test", 1, 2, 3, 4, 5, 6, 7, 8, 9);
++ exit(0);
++}
++]>>)
++changequote([,])
++
++dnl # test driver for va_copy() implementation
++m4_define(__va_copy_check, [
++ AH_VERBATIM($1,
++[/* Predefined possible va_copy() implementation (id: $1) */
++#define __VA_COPY_USE_$1(d, s) $2])
++ if test ".$ac_cv_va_copy" = .; then
++ AC_TRY_RUN(__va_copy_test($2), [ac_cv_va_copy="$1"])
++ fi
++])
++
++dnl # Autoconf check for va_copy() implementation checking
++AC_DEFUN(AC_CHECK_VA_COPY,[
++ dnl # provide Autoconf display check message
++ AC_MSG_CHECKING(for va_copy() function)
++ dnl # check for various implementations in priorized sequence
++ AC_CACHE_VAL(ac_cv_va_copy, [
++ ac_cv_va_copy=""
++ dnl # 1. check for standardized C99 macro
++ __va_copy_check(C99, [va_copy((d), (s))])
++ dnl # 2. check for alternative/deprecated GCC macro
++ __va_copy_check(GCM, [VA_COPY((d), (s))])
++ dnl # 3. check for internal GCC macro (high-level define)
++ __va_copy_check(GCH, [__va_copy((d), (s))])
++ dnl # 4. check for internal GCC macro (built-in function)
++ __va_copy_check(GCB, [__builtin_va_copy((d), (s))])
++ dnl # 5. check for assignment approach (assuming va_list is a struct)
++ __va_copy_check(ASS, [do { (d) = (s); } while (0)])
++ dnl # 6. check for assignment approach (assuming va_list is a pointer)
++ __va_copy_check(ASP, [do { *(d) = *(s); } while (0)])
++ dnl # 7. check for memory copying approach (assuming va_list is a struct)
++ __va_copy_check(CPS, [memcpy((void *)&(d), (void *)&(s)), sizeof((s))])
++ dnl # 8. check for memory copying approach (assuming va_list is a pointer)
++ __va_copy_check(CPP, [memcpy((void *)(d), (void *)(s)), sizeof(*(s))])
++ if test ".$ac_cv_va_copy" = .; then
++ AC_ERROR([no working implementation found])
++ fi
++ ])
++ dnl # optionally activate the fallback implementation
++ if test ".$ac_cv_va_copy" = ".C99"; then
++ AC_DEFINE(HAVE_VA_COPY, 1, [Define if va_copy() macro exists (and no fallback implementation is required)])
++ fi
++ dnl # declare which fallback implementation to actually use
++ AC_DEFINE_UNQUOTED([__VA_COPY_USE], [__VA_COPY_USE_$ac_cv_va_copy],
++ [Define to id of used va_copy() implementation])
++ dnl # provide activation hook for fallback implementation
++ AH_VERBATIM([__VA_COPY_ACTIVATION],
++[/* Optional va_copy() implementation activation */
++#ifndef HAVE_VA_COPY
++#define va_copy(d, s) __VA_COPY_USE(d, s)
++#endif
++])
++ dnl # provide Autoconf display result message
++ if test ".$ac_cv_va_copy" = ".C99"; then
++ AC_MSG_RESULT([yes])
++ else
++ AC_MSG_RESULT([no (using fallback implementation)])
++ fi
++])
++