Description:
------------
spread_receive() has default value of 0 for "timeout" parameter which means, effectively, "check if there is anything on queue, but do not wait".

making timeout "positive" leads to some waiting-time in seconds.

wanted functionality: be able to wait for message without timeout. a common implementation for such cases is using "-1" value.

putting patch in "reproduce code" field

Reproduce code:
---------------
diff --git a/php_spread.c b/php_spread.c
index 69d6928..f325e29 100644
--- a/php_spread.c
+++ b/php_spread.c
@@ -590,12 +590,19 @@ PHP_FUNCTION(spread_receive) {
                RETURN_FALSE;
        }
 
-       towait.tv_sec = (unsigned long)timeout;
-       towait.tv_usec = (unsigned long)(1000000.0 * (timeout - (double)towait.tv_sec));
-
        FD_ZERO(&readfs);
        FD_SET(*mbox, &readfs);
-       if((ret = select(*mbox+1, &readfs, NULL, &readfs, &towait)) !=1 ) {
+
+       if (-1 == timeout) {
+               ret = select(*mbox+1, &readfs, NULL, &readfs, NULL);
+       } else {
+               towait.tv_sec = (unsigned long)timeout;
+               towait.tv_usec = (unsigned long)(1000000.0 * (timeout - (double)towait.tv_sec));
+
+               ret = select(*mbox+1, &readfs, NULL, &readfs, &towait);
+       }
+
+       if(1 != ret) {
                RETURN_FALSE;
        }