[PATCH] maint.mk: add syntax-check rule: detect unnecessary #include <stddef.h>

[Jim Meyering]

Here's another prohibit-header-without-use rule.
Note that applying it manually to gnulib's .h files found a few:

git ls-files|grep '\.h$' \
  | xargs grep -l '^ *#include  *<stddef\.h>' \
  | xargs grep -wLE 'NULL|offsetof|ptrdiff_t|size_t|wchar_t'

  u64.h
  lib/uninorm/normalize-internal.h
  xreadlink.h

The xreadlink.h use is obviously unused so
I've removed it (2nd cset, below),
but I haven't looked at the others yet.

>From fdfca9a2199b627caf94d0dbfa17f252c7b6d54d Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Sun, 23 Jan 2011 18:54:42 +0100
Subject: [PATCH] maint.mk: add syntax-check rule: detect unnecessary #include 
<stddef.h>

* top/maint.mk (sc_prohibit_stddef_without_use): New rule.
---
 ChangeLog    |    5 +++++
 top/maint.mk |    7 +++++++
 2 files changed, 12 insertions(+), 0 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 5298191..203bec2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2011-01-23  Jim Meyering  <address@hidden>
+
+       maint.mk: add syntax-check rule: detect unnecessary #include <stddef.h>
+       * top/maint.mk (sc_prohibit_stddef_without_use): New rule.
+
 2011-01-21  Paul Eggert  <address@hidden>

        getopt: omit HAVE_OPTRESET, HAVE_GETOPT_CLIP from config.h
diff --git a/top/maint.mk b/top/maint.mk
index 5915814..606d42e 100644
--- a/top/maint.mk
+++ b/top/maint.mk
@@ -571,6 +571,13 @@ sc_prohibit_intprops_without_use:
        re='\<($(_intprops_syms_re)) *\('                               \
          $(_sc_header_without_use)

+_stddef_syms_re = NULL|offsetof|ptrdiff_t|size_t|wchar_t
+# Prohibit the inclusion of stddef.h without an actual use.
+sc_prohibit_stddef_without_use:
+       @h='<stddef.h>'                                                 \
+       re='\<($(_stddef_syms_re)) *\('                                 \
+         $(_sc_header_without_use)
+
 sc_obsolete_symbols:
        @prohibit='\<(HAVE''_FCNTL_H|O''_NDELAY)\>'                     \
        halt='do not use HAVE''_FCNTL_H or O'_NDELAY                    \
--
1.7.3.5.38.gb312b


>From 903ded6824ec18799b25957f51df356d91b43fd9 Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Sun, 23 Jan 2011 19:07:52 +0100
Subject: [PATCH] xreadlink.h: remove unnecessary #include

* lib/xreadlink.h: Don't include <stddef.h>.  It was not used.
---
 ChangeLog       |    3 +++
 lib/xreadlink.h |    2 --
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 203bec2..41c76b0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2011-01-23  Jim Meyering  <address@hidden>

+       xreadlink.h: remove unnecessary #include
+       * lib/xreadlink.h: Don't include <stddef.h>.  It was not used.
+
        maint.mk: add syntax-check rule: detect unnecessary #include <stddef.h>
        * top/maint.mk (sc_prohibit_stddef_without_use): New rule.

diff --git a/lib/xreadlink.h b/lib/xreadlink.h
index d7d17e8..fe608a4 100644
--- a/lib/xreadlink.h
+++ b/lib/xreadlink.h
@@ -18,8 +18,6 @@

 /* Written by Jim Meyering <address@hidden>  */

-#include <stddef.h>
-
 extern char *xreadlink (char const *filename);

 #if GNULIB_XREADLINKAT
--
1.7.3.5.38.gb312b