since GNU C++ (as of 3.2.1) does not allow attributes on labels.
Problem reported by Nelson H. F. Beebe.
invokes YYERROR. MacOS 10.2.3's buggy "smart preprocessor"
insists on the trailing semicolon. */
#if defined (__GNUC_MINOR__) && 2093 <= (__GNUC__ * 1000 + __GNUC_MINOR__)
+ /* GNU C++ (as of version 3.2.1) does not allow attributes on labels. */
+# ifndef __cplusplus
__attribute__ ((__unused__));
+# endif
#endif
]b4_location_if([ yylerrsp = yylsp;