Fixed the check for __builtin_popcountl for old compilers.

Old compilers used on some platforms (e.g. DragonFlyBSD) do not support __has_builtin, so now we fall back to #if define if __has_builtin is not found.

Signed-off-by: b-aaz <b-aazbsd@proton.me>

hw/xfree86/compat/ones.c

@@ -20,8 +20,12 @@ int
 Ones(unsigned long mask)
 {                               /* HACKMEM 169 */
     /* can't add a message here because this should be fast */
+#if defined __has_builtin
 #if __has_builtin(__builtin_popcountl)
     return __builtin_popcountl (mask);
+#endif
+#elif defined __builtin_popcountl
+    return __builtin_popcountl (mask);
 #else
     unsigned long y;