SDL_string.c: tidy-up gcc2 va_copy defines after previous haiku commit.
diff --git a/src/stdlib/SDL_string.c b/src/stdlib/SDL_string.c
index bc46aec..695fccb 100644
--- a/src/stdlib/SDL_string.c
+++ b/src/stdlib/SDL_string.c
@@ -32,9 +32,7 @@
/* Visual Studio 2013 tries to link with _vacopy in the C runtime. Newer versions do an inline assignment */
#undef va_copy
#define va_copy(dst, src) dst = src
-#endif
-
-#if __GNUC__ == 2
+#elif defined(__GNUC__) && (__GNUC__ < 3)
#define va_copy(to, from) __va_copy(to, from)
#endif