Merge pull request #1274 from sangshuduo/fix-mac-build-for-compar-fn-t

fix __compar_fn_t build issue on Mac

src/inc/tast.h

@@ -26,6 +26,7 @@ extern "C" {
 
 #include "taosmsg.h"
 #include "ttypes.h"
+#include "os.h"
 
 struct tSQLBinaryExpr;
 struct SSchema;