From b8f37a543cb5c22d6992b67da4d100b27f784320 Mon Sep 17 00:00:00 2001
From: Simon McVittie <smcv@collabora.com>
Date: Fri, 21 Oct 2022 14:48:26 +0100
Subject: [PATCH] glib: Always implement G_VA_COPY as va_copy()

C99 guarantees that va_copy() exists, so use it, instead of probing
for __va_copy(), va_copy(), or a reimplementation from first principles.

Signed-off-by: Simon McVittie <smcv@collabora.com>
---
 glib/glibconfig.h.in |  1 +
 glib/gutils.h        | 13 -------------
 meson.build          | 35 ++++-------------------------------
 3 files changed, 5 insertions(+), 44 deletions(-)

diff --git a/glib/glibconfig.h.in b/glib/glibconfig.h.in
index e93a7c866..100d42741 100644
--- a/glib/glibconfig.h.in
+++ b/glib/glibconfig.h.in
@@ -118,6 +118,7 @@ typedef unsigned @glib_intptr_type_define@ guintptr;
 
 @glib_os@
 
+#define G_VA_COPY va_copy
 @glib_vacopy@
 
 #define G_HAVE_ISO_VARARGS 1
diff --git a/glib/gutils.h b/glib/gutils.h
index d50ef709e..36e2b50f5 100644
--- a/glib/gutils.h
+++ b/glib/gutils.h
@@ -36,19 +36,6 @@
 
 G_BEGIN_DECLS
 
-/* Define G_VA_COPY() to do the right thing for copying va_list variables.
- * glibconfig.h may have already defined G_VA_COPY as va_copy or __va_copy.
- */
-#if !defined (G_VA_COPY)
-#  if defined (__GNUC__) && defined (__PPC__) && (defined (_CALL_SYSV) || defined (_WIN32))
-#    define G_VA_COPY(ap1, ap2)	  (*(ap1) = *(ap2))
-#  elif defined (G_VA_COPY_AS_ARRAY)
-#    define G_VA_COPY(ap1, ap2)	  memmove ((ap1), (ap2), sizeof (va_list))
-#  else /* va_list is a pointer */
-#    define G_VA_COPY(ap1, ap2)	  ((ap1) = (ap2))
-#  endif /* va_list is a pointer */
-#endif /* !G_VA_COPY */
-
 GLIB_AVAILABLE_IN_ALL
 const gchar *         g_get_user_name        (void);
 GLIB_AVAILABLE_IN_ALL
diff --git a/meson.build b/meson.build
index e93ed2c8d..c49815a9c 100644
--- a/meson.build
+++ b/meson.build
@@ -1646,38 +1646,11 @@ else
 endif
 
 # === va_copy checks ===
-# we currently check for all three va_copy possibilities, so we get
-# all results in config.log for bug reports.
 
-va_copy_func = ''
-foreach try_func : [ '__va_copy', 'va_copy' ]
-  if cc.compiles('''#include <stdarg.h>
-                    #include <stdlib.h>
-                    #ifdef _MSC_VER
-                    # include "msvc_recommended_pragmas.h"
-                    #endif
-                    void f (int i, ...) {
-                    va_list args1, args2;
-                    va_start (args1, i);
-                    @0@ (args2, args1);
-                    if (va_arg (args2, int) != 42 || va_arg (args1, int) != 42)
-                      exit (1);
-                    va_end (args1); va_end (args2);
-                    }
-                    int main() {
-                      f (0, 42);
-                      return 0;
-                    }'''.format(try_func),
-                    name : try_func + ' check')
-    va_copy_func = try_func
-  endif
-endforeach
-if va_copy_func != ''
-  glib_conf.set('G_VA_COPY', va_copy_func)
-  glib_vacopy = '#define G_VA_COPY ' + va_copy_func
-else
-  glib_vacopy = '/* #undef G_VA_COPY */'
-endif
+glib_vacopy = ''
+
+# We check for G_VA_COPY_AS_ARRAY for historical reasons, but we no longer
+# use it: use Standard C va_copy() instead.
 
 va_list_val_copy_prog = '''
   #include <stdarg.h>