basic + fundamental: Clean up includes

Split out of #37344.

src/basic/glob-util.h

@@ -1,11 +1,9 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 #pragma once
 
-#include <glob.h>
-#include <stdbool.h>
+#include <glob.h>       /* IWYU pragma: export */
 
-#include "macro.h"
-#include "string-util.h"
+#include "forward.h"
 
 /* Note: this function modifies pglob to set various functions. */
 int safe_glob(const char *path, int flags, glob_t *pglob);
@@ -19,7 +17,4 @@ int glob_non_glob_prefix(const char *path, char **ret);
 
 #define _cleanup_globfree_ _cleanup_(globfree)
 
-_pure_ static inline bool string_is_glob(const char *p) {
-        /* Check if a string contains any glob patterns. */
-        return !!strpbrk(p, GLOB_CHARS);
-}
+bool string_is_glob(const char *p) _pure_;