KWIML: Teach ABI about 'long long' on older GNU

Old GNU compilers do not define __SIZEOF_LONG_LONG__ or
__LONG_LONG_MAX__ but do provide a 64-bit 'long long' type.

Suggested-by: Rolf Eike Beer <[email protected]>

ABI.h.in

@@ -253,7 +253,9 @@ suppression macro @KWIML@_ABI_NO_VERIFY was defined.
 #  else
 #   define @KWIML@_ABI_SIZEOF_LONG_LONG 0
 #  endif
-# elif defined(__hpux) && !defined(__GNUC__) /* Old HP: no __HP_cc/__HP_aCC above */
+# elif defined(__GNUC__) /* GNU */
+#  define @KWIML@_ABI_SIZEOF_LONG_LONG 8
+# elif defined(__hpux) /* Old HP: no __HP_cc/__HP_aCC/__GNUC__ above */
 #  define @KWIML@_ABI_SIZEOF_LONG_LONG 8
 # endif
 #endif