show GCC version in INFO output.

src/redis.c

@@ -1425,6 +1425,7 @@ sds genRedisInfoString(char *section) {
             "redis_git_dirty:%d\r\n"
             "arch_bits:%s\r\n"
             "multiplexing_api:%s\r\n"
+            "gcc_version:%d.%d.%d\r\n"
             "process_id:%ld\r\n"
             "tcp_port:%d\r\n"
             "uptime_in_seconds:%ld\r\n"
@@ -1435,6 +1436,11 @@ sds genRedisInfoString(char *section) {
             strtol(redisGitDirty(),NULL,10) > 0,
             (sizeof(long) == 8) ? "64" : "32",
             aeGetApiName(),
+#ifdef __GNUC__
+            __GNUC__,__GNUC_MINOR__,__GNUC_PATCHLEVEL__,
+#else
+            0,0,0,
+#endif
             (long) getpid(),
             server.port,
             uptime,