new config-h module, to remove the need for -DHAVE_CONFIG_H

[Paul Eggert]

I installed this into gnulib, and will install the corresponding
coreutils patch in a few minutes.

The basic idea is that source files should include config.h
unconditionally, so that we needn't clutter "make" output with
-DHAVE_CONFIG_H.

I'd also like to change gnulib source code so that its instances of

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

are replaced by "#include <config.h>".  But one step at a time.


2006-08-25  Paul Eggert  <address@hidden>

        New config-h module, so that "make" output needn't be cluttered
        by -DHAVE_CONFIG_H.
        * MODULES.html.sh (Support for building libraries and executables):
        Add config-h.
        * modules/config-h: New file.
        * gnulib-tool (nl, sed_transform_lib_file): New vars.
        (func_import): Turn "#ifdef HAVE_CONFIG_H" to "#if 1" if
        the config-h module is used.
        * m4/config-h.m4: New file.

--- MODULES.html.sh     25 Aug 2006 23:14:53 -0000      1.142
+++ MODULES.html.sh     26 Aug 2006 06:35:36 -0000
@@ -2099,6 +2099,7 @@ func_all_modules ()
   func_echo "$element"
 
   func_begin_table
+  func_module config-h
   func_module configmake
   func_module dummy
   func_module elisp-comp
--- gnulib-tool 24 Aug 2006 13:48:29 -0000      1.143
+++ gnulib-tool 26 Aug 2006 06:35:36 -0000
@@ -59,6 +59,9 @@ if test -z "$SORT"; then
   SORT=sort
 fi
 
+nl='
+'
+
 # func_usage
 # outputs to stdout the --help usage message.
 func_usage ()
@@ -1226,6 +1229,23 @@ func_import ()
     done
   fi
 
+  # Determine script to apply to imported library files.
+  sed_transform_lib_file=
+  case $nl$modules$nl in
+    *"${nl}config-h$nl"*)
+      # Assume config.h exists, and that -DHAVE_CONFIG_H is omitted.
+      sed_transform_lib_file=$sed_transform_lib_file'
+       s/^#ifdef[       ]*HAVE_CONFIG_H[        ]*$/#if 1/
+      ' ;;
+  esac
+  if test -n "$lgpl"; then
+    # Update license.
+    sed_transform_lib_file=$sed_transform_lib_file'
+      s/GNU General/GNU Lesser General/g
+      s/version 2\([ ,]\)/version 2.1\1/g
+    '
+  fi
+
   # Determine final file list.
   func_modules_to_filelist
   echo "File list:"
@@ -1349,12 +1369,10 @@ func_import ()
     func_dest_tmpfilename "$g"
     func_lookup_file "$f"
     cp "$lookedup_file" "$tmpfile" || func_fatal_error "failed"
-    if test -n "$lgpl"; then
-      # Update license.
+    if test -n "sed_transform_lib_file"; then
       case "$f" in
         lib/*)
-          sed -e 's/GNU General/GNU Lesser General/g' \
-              -e 's/version 2\([ ,]\)/version 2.1\1/g' \
+          sed -e "$sed_transform_lib_file" \
             < "$lookedup_file" > "$tmpfile" || func_fatal_error "failed"
           ;;
       esac
--- /dev/null   2005-09-24 22:00:15.000000000 -0700
+++ m4/config-h.m4      2006-08-25 23:29:40.000000000 -0700
@@ -0,0 +1,13 @@
+# Say that -DHAVE_CONFIG_H is not needed.
+
+dnl Copyright (C) 2006 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Written by Paul Eggert.
+
+# This package's source files all include config.h unconditionally,
+# so there's no need to pass -DHAVE_CONFIG_H to the compiler.
+AC_DEFUN([gl_CONFIG_H],
+  [AC_CONFIG_COMMANDS_PRE([test "X$DEFS" = X-DHAVE_CONFIG_H && DEFS=])])
--- /dev/null   2005-09-24 22:00:15.000000000 -0700
+++ modules/config-h    2006-08-25 23:04:57.000000000 -0700
@@ -0,0 +1,20 @@
+Description:
+Assume config.h exists, to avoid -DHAVE_CONFIG_H clutter in 'make' output.
+
+Files:
+m4/config-h.m4
+
+Depends-on:
+
+configure.ac:
+gl_CONFIG_H
+
+Makefile.am:
+
+Include:
+
+License:
+LGPL
+
+Maintainer:
+Paul Eggert, Jim Meyering