AC_DEFINE whitespace

[Eric Blake]

I'm debating about committing this patch.  It shaves off a lot of blank lines 
in configure output.  But I also found at least one use case in the wild that 
changes semantics if I commit it:
http://lists.gnu.org/archive/html/bug-coreutils/2008-11/msg00049.html

By making AC_DEFINE no longer force a leading newline, users that define a 
shell variable then call AC_DEFINE on the same line have become localized 
assignments, rather than persistent.  How much should we worry about breaking 
existing scripts, given that I did not see much common use of
 var=val AC_DEFINE
in my searching?

From: Eric Blake <address@hidden>
Date: Tue, 11 Nov 2008 10:34:08 -0700
Subject: [PATCH] Whitespace reduction in configure.

* lib/autoconf/general.m4 (_AC_INIT_PREPARE, AC_CHECK_FILES):
Avoid empty lines.
* lib/autoconf/autoheader.m4 (AH_VERBATIM): Likewise.
* NEWS: Mention the fallout.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog                  |    6 ++++++
 NEWS                       |    4 ++++
 lib/autoconf/autoheader.m4 |    5 ++---
 lib/autoconf/general.m4    |   13 ++++++-------
 4 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index fc611ae..7a0e154 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2008-11-11  Eric Blake  <address@hidden>
 
+       Whitespace reduction in configure.
+       * lib/autoconf/general.m4 (_AC_INIT_PREPARE, AC_CHECK_FILES):
+       Avoid empty lines.
+       * lib/autoconf/autoheader.m4 (AH_VERBATIM): Likewise.
+       * NEWS: Mention the fallout.
+
        Reduce forks in AC_DEFINE.
        * lib/autoconf/general.m4 (_AC_DEFINE_Q_PRINT): New macro.
        (_AC_DEFINE_Q): Use it to avoid forks for all AC_DEFINE and most
diff --git a/NEWS b/NEWS
index f5f3d6e..d8cb06d 100644
--- a/NEWS
+++ b/NEWS
@@ -43,6 +43,10 @@ GNU Autoconf NEWS - User visible changes.
    the call site, but since most users did not add dnl, this generally
    results in fewer empty lines in configure.
 
+** The autoconf macros AC_DEFINE and AC_DEFINE_UNQUOTED now output
+   fewer blank lines.  This generally is not a problem, but changes
+   semantics for any users that did 'var=value AC_DEFINE(...)'.
+
 
 * Major changes in Autoconf 2.63 (2008-09-09) [stable]
   Released by Eric Blake, based on git versions 2.62.*.
diff --git a/lib/autoconf/autoheader.m4 b/lib/autoconf/autoheader.m4
index 185c0e4..dfc5f77 100644
--- a/lib/autoconf/autoheader.m4
+++ b/lib/autoconf/autoheader.m4
@@ -2,7 +2,7 @@
 # Interface with autoheader.
 
 # Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001,
-# 2002 Free Software Foundation, Inc.
+# 2002, 2008 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -68,8 +68,7 @@ m4_define([AH_OUTPUT], [])
 # Quote for Perl '' strings, which are those used by Autoheader.
 m4_define([AH_VERBATIM],
 [AS_LITERAL_IF([$1],
-              [AH_OUTPUT([$1], AS_ESCAPE([[$2]], [\\'']))])
-])
+              [AH_OUTPUT([$1], AS_ESCAPE([[$2]], [\\'']))])])
 
 
 # AH_TEMPLATE(KEY, DESCRIPTION)
diff --git a/lib/autoconf/general.m4 b/lib/autoconf/general.m4
index d60e302..295b531 100644
--- a/lib/autoconf/general.m4
+++ b/lib/autoconf/general.m4
@@ -1333,16 +1333,16 @@ AS_ECHO(["/* confdefs.h */"]) > confdefs.h
 
 # Predefined preprocessor variables.
 AC_DEFINE_UNQUOTED([PACKAGE_NAME], ["$PACKAGE_NAME"],
-                  [Define to the full name of this package.])
+                  [Define to the full name of this package.])dnl
 AC_DEFINE_UNQUOTED([PACKAGE_TARNAME], ["$PACKAGE_TARNAME"],
-                  [Define to the one symbol short name of this package.])
+                  [Define to the one symbol short name of this package.])dnl
 AC_DEFINE_UNQUOTED([PACKAGE_VERSION], ["$PACKAGE_VERSION"],
-                  [Define to the version of this package.])
+                  [Define to the version of this package.])dnl
 AC_DEFINE_UNQUOTED([PACKAGE_STRING], ["$PACKAGE_STRING"],
-                  [Define to the full name and version of this package.])
+                  [Define to the full name and version of this package.])dnl
 AC_DEFINE_UNQUOTED([PACKAGE_BUGREPORT], ["$PACKAGE_BUGREPORT"],
                   [Define to the address where bug reports for this package
-                   should be sent.])
+                   should be sent.])dnl
 
 # Let the site file select an alternate cache file if it wants to.
 AC_SITE_LOAD
@@ -2740,8 +2740,7 @@ m4_define([_AC_CHECK_FILES],
 # ACTION-IF-FOUND or ACTION-IF-NOT-FOUND.  For files that exist, also
 # provide the preprocessor variable HAVE_FILE.
 AC_DEFUN([AC_CHECK_FILES],
-[m4_map_args_w([$1], [AC_CHECK_FILE(_$0(], [)[
-$2], [$3])])])
+[m4_map_args_w([$1], [AC_CHECK_FILE(_$0(], [)[$2], [$3])])])
 
 
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