ignore leading spaces when checking for a suitable subprotocol

My Browsers send as Subprotocols e.g. chat, superchat, mySubprotocol (with spaces after the ,). Libwebsockets now checked if ' mySubprotocol' was equal to 'mySubprotocol' which failed. With this fix the leading space is ignored and uses 'mySubprotocol' for comparision.

lib/server.c

@@ -1141,7 +1141,7 @@ lws_handshake_server(struct lws *wsi, unsigned char **buf, size_t len)
 	struct lws_context_per_thread *pt = &context->pt[(int)wsi->tsi];
 	struct _lws_header_related hdr;
 	struct allocated_headers *ah;
-	int protocol_len, n = 0, hit;
+	int protocol_len, n = 0, hit, non_space_char_found = 0;
 	char protocol_list[128];
 	char protocol_name[64];
 	char *p;
@@ -1341,8 +1341,17 @@ lws_handshake_server(struct lws *wsi, unsigned char **buf, size_t len)
 
 		while (*p && !hit) {
 			n = 0;
-			while (n < sizeof(protocol_name) - 1 && *p && *p !=',')
+			non_space_char_found = 0;
+			while (n < sizeof(protocol_name) - 1 && *p &&
+			       *p != ',') {
+				// ignore leading spaces
+				if (!non_space_char_found && *p == ' ') {
+					n++;
+					continue;
+				}
+				non_space_char_found = 1;
 				protocol_name[n++] = *p++;
+			}
 			protocol_name[n] = '\0';
 			if (*p)
 				p++;