Fix compilation issues on OS X - mainly #include file changes (Lars Immisch)

diff --git a/include/openbsc/paging.h b/include/openbsc/paging.h
index fd9dc02..de512d1 100644
--- a/include/openbsc/paging.h
+++ b/include/openbsc/paging.h
@@ -21,7 +21,7 @@
 #ifndef PAGING_H
 #define PAGING_H
 
-#include <malloc.h>
+#include <stdlib.h>
 #include <string.h>
 
 #include "linuxlist.h"