missing_resource.h: RLIMIT_RTTIME is defined since glibc-2.14

Now our baseline is glibc-2.31.

src/basic/missing_resource.h

@@ -1,15 +0,0 @@
-/* SPDX-License-Identifier: LGPL-2.1-or-later */
-#pragma once
-
-#include <sys/resource.h>
-
-#include "macro.h"
-
-#ifndef RLIMIT_RTTIME
-#  define RLIMIT_RTTIME 15
-#else
-assert_cc(RLIMIT_RTTIME == 15);
-#endif
-
-/* If RLIMIT_RTTIME is not defined, then we cannot use RLIMIT_NLIMITS as is */
-#define _RLIMIT_MAX (RLIMIT_RTTIME+1 > RLIMIT_NLIMITS ? RLIMIT_RTTIME+1 : RLIMIT_NLIMITS)

src/basic/rlimit-util.c

@@ -9,7 +9,6 @@
 #include "fileio.h"
 #include "format-util.h"
 #include "macro.h"
-#include "missing_resource.h"
 #include "process-util.h"
 #include "rlimit-util.h"
 #include "string-table.h"

src/basic/rlimit-util.h

@@ -4,7 +4,8 @@
 #include <sys/resource.h>
 
 #include "macro.h"
-#include "missing_resource.h"
+
+#define _RLIMIT_MAX RLIMIT_NLIMITS
 
 const char* rlimit_to_string(int i) _const_;
 int rlimit_from_string(const char *s) _pure_;