Mapper, ...: use memcmp() instead of strncmp() where appropriate

Micro-optimization.

src/input/CurlInputPlugin.cxx

@@ -1084,8 +1084,8 @@ static struct input_stream *
 input_curl_open(const char *url, Mutex &mutex, Cond &cond,
 		Error &error)
 {
-	if ((strncmp(url, "http://",  7) != 0) &&
-	    (strncmp(url, "https://", 8) != 0))
+	if (memcmp(url, "http://",  7) != 0 &&
+	    memcmp(url, "https://", 8) != 0)
 		return NULL;
 
 	struct input_curl *c = new input_curl(url, mutex, cond);