util-lib: split out allocation calls into alloc-util.[ch]

src/basic/unit-name.c

@@ -22,6 +22,7 @@
 #include <errno.h>
 #include <string.h>
 
+#include "alloc-util.h"
 #include "bus-label.h"
 #include "def.h"
 #include "hexdecoct.h"