Update cxxabi-compat.cpp

remove compiler warning about unused parameters

Author: stevstrong

STM32F1/cores/maple/cxxabi-compat.cpp

@@ -14,6 +14,7 @@ extern "C" char * __cxa_demangle (const char *mangled_name,
                                   char *output_buffer,
                                   size_t *length,
                                   int *status) {
+  (void)length; (void)status;
   strcpy((char*)mangled_name, output_buffer);
   return output_buffer;
 }