[PATCH] Fix typo

[XiaoBing Jiang]

# HG changeset patch
# User s7v7nislands <s7v7nislands at gmail.com>
# Date 1411437071 -28800
#      Tue Sep 23 09:51:11 2014 +0800
# Branch fix_typo
# Node ID 34a7a94c3dab57fd302fe731b013d90be4354efe
# Parent  a0a14319968b2d978d306f5a91e81e9e4e3e7ce6
Fix typo

diff -r a0a14319968b -r 34a7a94c3dab src/event/ngx_event_mutex.c
--- a/src/event/ngx_event_mutex.c Mon Sep 22 19:48:23 2014 +0400
+++ b/src/event/ngx_event_mutex.c Tue Sep 23 09:51:11 2014 +0800
@@ -28,7 +28,7 @@
         m->last = ev;
         ev->next = NULL;

-#if (NGX_THREADS0)
+#if (NGX_THREADS)
         ev->light = 1;
 #endif