tmpfiles: do not bump access times of directories we are cleaning up

Both plain opendir() and glob() will bump access time. Privileged
option O_NOATIME can be used to prevent the access time from being
updated. We already used it for subdirectories of the directories
which we were cleaning up. But for the directories specified directly
in the config files, we wouldn't do that. This means that,
paradoxically, our own temporary directories for PrivateTmp would stay
around forever, as long as one let systemd-tmpfiles-clean.service run
regularly, because they had their own glob patterns specified.

https://bugzilla.redhat.com/show_bug.cgi?id=1183684

src/shared/macro.h

@@ -67,6 +67,10 @@
         _Pragma("GCC diagnostic push");                                 \
         _Pragma("GCC diagnostic ignored \"-Wshadow\"")
 
+#define DISABLE_WARNING_INCOMPATIBLE_POINTER_TYPES                      \
+        _Pragma("GCC diagnostic push");                                 \
+        _Pragma("GCC diagnostic ignored \"-Wincompatible-pointer-types\"")
+
 #define REENABLE_WARNING                                                \
         _Pragma("GCC diagnostic pop")