RFC: AC_REQUIRE_AUX_DIR trace hook

[Alexandre Duret-Lutz]

This patch adds a trace hook to list expected auxiliary scripts.
For instance AC_PROG_INSTALL requires install-sh, and AC_CANONICAL_* 
require config.{sub,guess}.  

Doing so will allow to simplify Automake by removing some
hard-coded knowledge.  It'll also let third-party macro express
their requirements (the benefit is that Automake will
automatically distribute these files, users won't have to
EXTRA_DIST these files by hand).

I've mentioned AM_REQUIRE_AUX_DIR in
http://lists.gnu.org/archive/html/automake/2004-07/msg00128.html
but when I started implementing this in Automake I realized the
macro would be better in Autoconf since it would make it
possible to document Autoconf's own expectations.

OK to commit?

I have yet to finish the Automake couterpart to that patch,
before proceeding; that should be done tomorrow.  Then I'd like
to submit a harmless one-liner to libtool to declare the
ltmain.in dependency before they make a release.

2004-08-02  Alexandre Duret-Lutz  <address@hidden>

        * lib/autoconf/general.m4 (AC_REQUIRE_AUX_FILE): New empty macro.
        (AC_CANONICAL_BUILD): Call it to require config.sub and config.guess.
        * lib/autoconf/programs.m4 (AC_PROG_INSTALL): Likewise for install-sh.
        * doc/autoconf.texi (Input): Document AC_REQUIRE_AUX_FILE.
        * lib/autom4te.in (Automake-preselections): Preselect
        AC_REQUIRE_AUX_FILE.  Automake 1.10 will trace it.

Index: NEWS
===================================================================
RCS file: /cvsroot/autoconf/autoconf/NEWS,v
retrieving revision 1.327
diff -u -r1.327 NEWS
--- NEWS        19 Mar 2004 08:57:51 -0000      1.327
+++ NEWS        2 Aug 2004 22:11:28 -0000
@@ -13,6 +13,9 @@
   New macros that detect programs whose name is prefixed with the
   target type, if the build type and target type are different.
 
+** AC_REQUIRE_AUX_FILE
+  New trace macro that declares expected auxiliary files.
+
 * Major changes in Autoconf 2.59a
 
 ** AC_PROG_GREP
Index: doc/autoconf.texi
===================================================================
RCS file: /cvsroot/autoconf/autoconf/doc/autoconf.texi,v
retrieving revision 1.825
diff -u -r1.825 autoconf.texi
--- doc/autoconf.texi   30 Jul 2004 00:34:27 -0000      1.825
+++ doc/autoconf.texi   2 Aug 2004 22:11:40 -0000
@@ -1765,6 +1765,16 @@
 to MS-DOS, because the filename @file{aux} is reserved under MS-DOS.
 @end defmac
 
address@hidden AC_REQUIRE_AUX_FILE (@var{file})
address@hidden
+Declares that @var{file} is expected in the directory defined above.  In
+Autoconf proper, this macro does nothing: its sole purpose is to be
+traced by third-party tools to produce a list of expected auxiliary
+files.  For instance it is called by macros like @code{AC_PROG_INSTALL}
+(@pxref{Particular Programs}) or @code{AC_CANONICAL_BUILD}
+(@pxref{Canonicalizing}) to register the auxiliary files they need.
address@hidden defmac
+
 Similarly, packages that use @command{aclocal} should declare where
 local macros can be found using @code{AC_CONFIG_MACRO_DIR}.
 
Index: lib/autom4te.in
===================================================================
RCS file: /cvsroot/autoconf/autoconf/lib/autom4te.in,v
retrieving revision 1.25
diff -u -r1.25 autom4te.in
--- lib/autom4te.in     1 Aug 2004 22:30:37 -0000       1.25
+++ lib/autom4te.in     2 Aug 2004 22:11:40 -0000
@@ -48,6 +48,7 @@
 args: --preselect AC_CONFIG_LINKS
 args: --preselect AC_INIT
 args: --preselect AC_LIBSOURCE
+args: --preselect AC_REQUIRE_AUX_FILE
 args: --preselect AC_SUBST
 args: --preselect AM_AUTOMAKE_VERSION
 args: --preselect AM_CONDITIONAL
Index: lib/autoconf/general.m4
===================================================================
RCS file: /cvsroot/autoconf/autoconf/lib/autoconf/general.m4,v
retrieving revision 1.830
diff -u -r1.830 general.m4
--- lib/autoconf/general.m4     28 Jan 2004 22:21:16 -0000      1.830
+++ lib/autoconf/general.m4     2 Aug 2004 22:11:41 -0000
@@ -1563,6 +1563,19 @@
 
 
 
+## --------------------- ##
+## Requiring aux files.  ##
+## --------------------- ##
+
+# AC_REQUIRE_AUX_FILE(FILE)
+# -------------------------
+# This macro does nothing, it's a hook to be read with `autoconf --trace'.
+# It announces FILE is required in the auxdir.
+m4_define([AC_REQUIRE_AUX_FILE],
+[AS_LITERAL_IF([$1], [],
+               [AC_FATAL([$0: requires a literal argument])])])
+
+
 
 ## ----------------------------------- ##
 ## Getting the canonical system type.  ##
@@ -1596,6 +1609,8 @@
 # ------------------
 AC_DEFUN_ONCE([AC_CANONICAL_BUILD],
 [AC_REQUIRE([AC_CONFIG_AUX_DIR_DEFAULT])dnl
+AC_REQUIRE_AUX_FILE([config.sub])dnl
+AC_REQUIRE_AUX_FILE([config.guess])dnl
 m4_divert_text([HELP_CANON],
 [[
 System types:
Index: lib/autoconf/programs.m4
===================================================================
RCS file: /cvsroot/autoconf/autoconf/lib/autoconf/programs.m4,v
retrieving revision 1.30
diff -u -r1.30 programs.m4
--- lib/autoconf/programs.m4    10 May 2004 18:54:37 -0000      1.30
+++ lib/autoconf/programs.m4    2 Aug 2004 22:11:42 -0000
@@ -512,6 +512,7 @@
 AN_PROGRAM([install], [AC_PROG_INSTALL])
 AC_DEFUN([AC_PROG_INSTALL],
 [AC_REQUIRE([AC_CONFIG_AUX_DIR_DEFAULT])dnl
+AC_REQUIRE_AUX_FILE([install-sh])dnl
 # Find a good install program.  We prefer a C program (faster),
 # so one script is as good as another.  But avoid the broken or
 # incompatible versions:
-- 
Alexandre Duret-Lutz