Don't define _STDARG_H/etc. if not gcc, it may collide with system's header.

From-SVN: r6527

gcc/ginclude/stdarg.h

@@ -3,6 +3,12 @@
    actual type **after default promotions**.
    Thus, va_arg (..., short) is not valid.  */
 
+#ifndef __GNUC__
+/* Use the system's macros with the system's compiler.
+   This is relevant only when building GCC with some other compiler.  */
+#include <stdarg.h>
+#else
+
 #ifndef _STDARG_H
 #ifndef _ANSI_STDARG_H_
 #ifndef __need___va_list
@@ -11,11 +17,6 @@
 #endif /* not __need___va_list */
 #undef __need___va_list
 
-#ifndef __GNUC__
-/* Use the system's macros with the system's compiler.
-   This is relevant only when building GCC with some other compiler.  */
-#include <stdarg.h>
-#else
 #ifdef __clipper__
 #include <va-clipper.h>
 #else
@@ -155,6 +156,6 @@ typedef __gnuc_va_list va_list;
 
 #endif /* _STDARG_H */
 
-#endif /* __GNUC__ */
 #endif /* not _ANSI_STDARG_H_ */
 #endif /* not _STDARG_H */
+#endif /* __GNUC__ */