shared: add process-util.[ch]

src/libsystemd/sd-bus/bus-container.c

@@ -23,6 +23,7 @@
 #include <fcntl.h>
 
 #include "util.h"
+#include "process-util.h"
 #include "bus-internal.h"
 #include "bus-socket.h"
 #include "bus-container.h"

src/libsystemd/sd-bus/bus-creds.c

@@ -24,6 +24,7 @@
 
 #include "util.h"
 #include "formats-util.h"
+#include "process-util.h"
 #include "capability.h"
 #include "cgroup-util.h"
 #include "fileio.h"