Let DRD print a warning at startup that support for Darwin is still considered experimental, and filter out this warning from the regression tests.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@10554 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/drd/drd_main.c b/drd/drd_main.c
index 3fde8d2..b3b3708 100644
--- a/drd/drd_main.c
+++ b/drd/drd_main.c
@@ -544,8 +544,12 @@
 
 static void DRD_(post_clo_init)(void)
 {
-#if !defined(VGO_linux) && !defined(VGO_darwin)
-   VG_(printf)("\nWARNING: DRD has only been tested on Linux and on Darwin.\n\n");
+#if defined(VGO_linux)
+   /* fine */
+#elif defined(VGO_darwin)
+   VG_(printf)("\nWARNING: DRD support for Darwin is still considered as experimental.\n\n");
+#else
+   VG_(printf)("\nWARNING: DRD has not yet been tested on this operating system.\n\n");
 #  endif
 
    if (DRD_(s_var_info))