use compiler builtins for variadic macros when available

[musl] / include / stdarg.h

diff --git a/include/stdarg.h b/include/stdarg.h
index 2e18e5f..60d4e2a 100644 (file)
--- a/include/stdarg.h
+++ b/include/stdarg.h
@@ -9,7 +9,14 @@ extern "C" {
 
 #include <bits/alltypes.h>
 
+#if __GNUC__ >= 3
+#define va_start(v,l)   __builtin_va_start(v,l)
+#define va_end(v)       __builtin_va_end(v)
+#define va_arg(v,l)     __builtin_va_arg(v,l)
+#define va_copy(d,s)    __builtin_va_copy(d,s)
+#else
 #include <bits/stdarg.h>
+#endif
 
 #ifdef __cplusplus
 }