Use the right #ifdef test for sys/mman.h.

Based on patch by Travis Vitek.


git-svn-id: https://snappy.googlecode.com/svn/trunk@47 03e5f5b5-db94-4691-08a0-1a8bf15f6143

snappy-stubs-internal.h

diff --git a/snappy-stubs-internal.h b/snappy-stubs-internal.h
index 46ee235..cc51e26 100644
--- a/snappy-stubs-internal.h
+++ b/snappy-stubs-internal.h
@@ -42,7 +42,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-#ifdef HAVE_SYS_MMAN
+#ifdef HAVE_SYS_MMAN_H
 #include <sys/mman.h>
 #endif