SDL: haiku: updated for Haiku (d37c9)

From d37c9777b97980810db7e2b16f34cabadec7f548 Mon Sep 17 00:00:00 2001
From: kenmays <[EMAIL REDACTED]>
Date: Wed, 12 Jan 2022 06:48:00 -0800
Subject: [PATCH] haiku: updated for Haiku

---
 src/stdlib/SDL_string.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/stdlib/SDL_string.c b/src/stdlib/SDL_string.c
index 12cc2da8f5b..bc46aecf6cd 100644
--- a/src/stdlib/SDL_string.c
+++ b/src/stdlib/SDL_string.c
@@ -34,6 +34,10 @@
 #define va_copy(dst, src)   dst = src
 #endif
 
+#if __GNUC__ == 2
+#define va_copy(to, from)   __va_copy(to, from)
+#endif
+
 #if !defined(HAVE_VSSCANF) || !defined(HAVE_STRTOL) || !defined(HAVE_STRTOUL) || !defined(HAVE_STRTOD) || !defined(HAVE_STRTOLL) || !defined(HAVE_STRTOULL)
 #define SDL_isupperhex(X)   (((X) >= 'A') && ((X) <= 'F'))
 #define SDL_islowerhex(X)   (((X) >= 'a') && ((X) <= 'f'))