basic + fundamental: Clean up includes

Split out of #37344.

src/basic/env-util.c

@@ -1,22 +1,17 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
-#include <errno.h>
-#include <limits.h>
-#include <stdarg.h>
 #include <stdlib.h>
 #include <unistd.h>
 
 #include "alloc-util.h"
 #include "env-util.h"
 #include "errno-util.h"
-#include "escape.h"
 #include "extract-word.h"
+#include "format-util.h"
 #include "log.h"
-#include "macro.h"
 #include "parse-util.h"
 #include "path-util.h"
 #include "process-util.h"
-#include "stdio-util.h"
 #include "string-util.h"
 #include "strv.h"
 #include "syslog-util.h"
@@ -27,6 +22,12 @@
         DIGITS LETTERS                          \
         "_"
 
+size_t sc_arg_max(void) {
+        long l = sysconf(_SC_ARG_MAX);
+        assert(l > 0);
+        return (size_t) l;
+}
+
 static bool env_name_is_valid_n(const char *e, size_t n) {
 
         if (n == SIZE_MAX)