Introduce CONF_DIRS_NULSTR helper to define standard conf dirs
Several different systemd tools define a nulstr containing a standard
series of configuration file directories, in /etc, /run, /usr/local/lib,
/usr/lib, and (#ifdef HAVE_SPLIT_USR) /lib. Factor that logic out into
a new helper macro, CONF_DIRS_NULSTR.
diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c
index 1e4675f..23fd6ca 100644
--- a/src/tmpfiles/tmpfiles.c
+++ b/src/tmpfiles/tmpfiles.c
@@ -117,15 +117,7 @@
static char **arg_exclude_prefixes = NULL;
static char *arg_root = NULL;
-static const char conf_file_dirs[] =
- "/etc/tmpfiles.d\0"
- "/run/tmpfiles.d\0"
- "/usr/local/lib/tmpfiles.d\0"
- "/usr/lib/tmpfiles.d\0"
-#ifdef HAVE_SPLIT_USR
- "/lib/tmpfiles.d\0"
-#endif
- ;
+static const char conf_file_dirs[] = CONF_DIRS_NULSTR("tmpfiles");
#define MAX_DEPTH 256