basic + fundamental: Clean up includes

Split out of #37344.

src/basic/devnum-util.c

@@ -9,6 +9,7 @@
 #include "devnum-util.h"
 #include "parse-util.h"
 #include "path-util.h"
+#include "stdio-util.h"
 #include "string-util.h"
 
 int parse_devnum(const char *s, dev_t *ret) {
@@ -135,3 +136,7 @@ int device_path_parse_major_minor(const char *path, mode_t *ret_mode, dev_t *ret
 
         return 0;
 }
+
+char* format_devnum(dev_t d, char buf[static DEVNUM_STR_MAX]) {
+        return ASSERT_PTR(snprintf_ok(buf, DEVNUM_STR_MAX, DEVNUM_FORMAT_STR, DEVNUM_FORMAT_VAL(d)));
+}