[PATCH] backupfile: remove unnecessary use of m4/dos.m4

[Paul Eggert]

Further Emacs hacking has shown the need to break more dependencies
in gnulib.

In particular, m4/dos.m4 needs to go.  It laboriously
invokes the C compiler, and extracts symbols from it, puts them
into config.h; but it's much easier to use the symbols
directly.  filename.h already does this, but it disagrees with
dos.m4 in some respects.  What I'll try to do is come up with
a different include file dosname.h that packages up dos.m4,
and then later we can work on merging filename.h and dosname.h.

The first and simplest step is to modify backupfile, which doesn't
need to use these symbols at all.  I pushed this:

* m4/backupfile.m4 (gl_BACKUPFILE): Don't require gl_AC_DOS; none
of its symbols are used by the backupfile code.  backupfile.c does
use a symbol HAVE_DOS_FILE_NAMES, but that symbol is meant only
for the rare case of programs that want all their backup file
names to live within 8+3 limits, and dos.m4 doesn't address that.
* modules/backupfile (Files): Remove m4/dos.m4.
---
 ChangeLog          |   10 ++++++++++
 m4/backupfile.m4   |    3 +--
 modules/backupfile |    1 -
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 7795cce..b739e06 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2011-02-24  Paul Eggert  <address@hidden>
+
+       backupfile: remove unnecessary use of m4/dos.m4
+       * m4/backupfile.m4 (gl_BACKUPFILE): Don't require gl_AC_DOS; none
+       of its symbols are used by the backupfile code.  backupfile.c does
+       use a symbol HAVE_DOS_FILE_NAMES, but that symbol is meant only
+       for the rare case of programs that want all their backup file
+       names to live within 8+3 limits, and dos.m4 doesn't address that.
+       * modules/backupfile (Files): Remove m4/dos.m4.
+
 2011-02-24  Jim Meyering  <address@hidden>
 
        strstr: fix a bug whereby strstr would mistakenly return NULL
diff --git a/m4/backupfile.m4 b/m4/backupfile.m4
index 1dce383..ac9559e 100644
--- a/m4/backupfile.m4
+++ b/m4/backupfile.m4
@@ -1,4 +1,4 @@
-# backupfile.m4 serial 12
+# backupfile.m4 serial 13
 dnl Copyright (C) 2002-2006, 2009-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -10,7 +10,6 @@ AC_DEFUN([gl_BACKUPFILE],
 
   dnl Prerequisites of lib/backupfile.c.
   AC_REQUIRE([gl_CHECK_TYPE_STRUCT_DIRENT_D_INO])
-  AC_REQUIRE([gl_AC_DOS])
   AC_REQUIRE([AC_SYS_LONG_FILE_NAMES])
   AC_CHECK_FUNCS_ONCE([pathconf])
 ])
diff --git a/modules/backupfile b/modules/backupfile
index fcfcce6..0258817 100644
--- a/modules/backupfile
+++ b/modules/backupfile
@@ -5,7 +5,6 @@ variables.
 Files:
 lib/backupfile.h
 lib/backupfile.c
-m4/dos.m4
 m4/backupfile.m4
 
 Depends-on:
-- 
1.7.4