[Automake-NG] [FYI] [ng] refactor: drop use of ?HOST?, ?BUILD? and ?TARGET? transforms

[Stefano Lattarini]

Instead, use the new make variables $(am.conf.host-triplet),
$(am.conf.build-triplet) and $(am.conf.host-triplet) are defined.

* automake.in (preprocess_file): Drop 'HOST', 'BUILD' and 'TARGET'
transforms.  Their role taken over ...
(generate_makefile): ... by the new variables 'am.conf.host-triplet',
'am.conf.build-triplet' and 'am.conf.target-triplet' defined here.
* lib/am/dejagnu.am: Adjust.
* t/triplet.sh: New test.

Signed-off-by: Stefano Lattarini <address@hidden>
---
 automake.in       | 14 +++++++----
 lib/am/dejagnu.am | 12 ++++-----
 t/triplet.sh      | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+), 11 deletions(-)
 create mode 100755 t/triplet.sh

diff --git a/automake.in b/automake.in
index c50e0ad..4e28402 100644
--- a/automake.in
+++ b/automake.in
@@ -5707,10 +5707,6 @@ sub preprocess_file ($%)
                 'SUBDIRS'      => !! var ('SUBDIRS'),
                 'TOPDIR_P'     => $relative_dir eq '.',
 
-                'BUILD'    => ($seen_canonical >= AC_CANONICAL_BUILD),
-                'HOST'     => ($seen_canonical >= AC_CANONICAL_HOST),
-                'TARGET'   => ($seen_canonical >= AC_CANONICAL_TARGET),
-
                 'LIBTOOL'      => !! var ('LIBTOOL'),
                 'NONLIBTOOL'   => 1,
                 'SILENT'       => silent_flag (),
@@ -6707,7 +6703,8 @@ sub generate_makefile ($$)
        }
     }
 
-  # Must do this after reading .am file.
+  # Some of these must do this after reading .am file.
+
   define_variable ('subdir', INTERNAL, $relative_dir);
   define_variable ('am.conf.is-topdir', INTERNAL,
                    $relative_dir eq '.' ? "yes" : "");
@@ -6718,6 +6715,13 @@ sub generate_makefile ($$)
   define_variable ('am.relpath.makefile.in', INTERNAL,
                    prepend_srcdir ($makefile_in));
 
+  define_variable 'am.conf.build-triplet', INTERNAL,
+                  $seen_canonical >= AC_CANONICAL_BUILD ? '$(build)' : '';
+  define_variable 'am.conf.host-triplet', INTERNAL,
+                  $seen_canonical >= AC_CANONICAL_HOST ? '$(host)' : '';
+  define_variable 'am.conf.target-triplet', INTERNAL,
+                  $seen_canonical >= AC_CANONICAL_TARGET ? '$(target)' : '';
+
   # If DIST_SUBDIRS is defined, make sure SUBDIRS is, so that
   # recursive rules are enabled.
   define_variable ('SUBDIRS', INTERNAL, '')
diff --git a/lib/am/dejagnu.am b/lib/am/dejagnu.am
index 42ba485..c3a9659 100644
--- a/lib/am/dejagnu.am
+++ b/lib/am/dejagnu.am
@@ -55,12 +55,12 @@ site.exp: Makefile $(EXTRA_DEJAGNU_SITE_CONFIG)
        @echo 'set srcdir "$(srcdir)"' >>site.tmp
        @echo "set objdir `pwd`" >>site.tmp
 ## Quote the *_alias variables because they might be empty.
-?BUILD?        @echo 'set build_alias "$(build_alias)"' >>site.tmp
-?BUILD?        @echo 'set build_triplet $(build)' >>site.tmp
-?HOST? @echo 'set host_alias "$(host_alias)"' >>site.tmp
-?HOST? @echo 'set host_triplet $(host)' >>site.tmp
-?TARGET?       @echo 'set target_alias "$(target_alias)"' >>site.tmp
-?TARGET?       @echo 'set target_triplet $(target)' >>site.tmp
+       $(if $(am.conf.build-triplet),@echo 'set build_triplet $(build)' 
>>site.tmp)
+       $(if $(am.conf.build-triplet),@echo 'set build_alias "$(build_alias)"' 
>>site.tmp)
+       $(if $(am.conf.host-triplet),@echo 'set host_triplet $(host)' 
>>site.tmp)
+       $(if $(am.conf.host-triplet),@echo 'set host_alias "$(host_alias)"' 
>>site.tmp)
+       $(if $(am.conf.target-triplet),@echo 'set target_alias 
"$(target_alias)"' >>site.tmp)
+       $(if $(am.conf.target-triplet),@echo 'set target_triplet $(target)' 
>>site.tmp)
 ## Allow the package author to extend site.exp.
        @list='$(EXTRA_DEJAGNU_SITE_CONFIG)'; for f in $$list; do \
          echo "## Begin content included from file $$f.  Do not modify. ##" \
diff --git a/t/triplet.sh b/t/triplet.sh
new file mode 100755
index 0000000..f2796c3
--- /dev/null
+++ b/t/triplet.sh
@@ -0,0 +1,73 @@
+#! /bin/sh
+# Copyright (C) 2012 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
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# The $(host), $(build), $(target) variables, and their '*_alias'
+# and 'am.conf.*-triplet' counterparts.
+
+. ./defs || exit 1
+
+: > config.guess
+: > config.sub
+: > Makefile.am
+
+$ACLOCAL
+$AUTOMAKE
+grep "^am\.conf\.host-triplet = *$" Makefile.in
+grep "^am\.conf\.build-triplet = *$" Makefile.in
+grep "^am\.conf\.target-triplet = *$" Makefile.in
+
+mv -f configure.ac configure.tmpl
+
+for M in HOST BUILD TARGET; do
+  m=$(echo $M | LC_ALL=C tr '[A-Z]' '[a-z]')
+  (cat configure.tmpl && echo AC_CANONICAL_$M) > configure.ac
+  rm -rf autom4te.cache
+  $AUTOMAKE
+  grep "^$m = @address@hidden" Makefile.in
+  grep "^${m}_alias = @address@hidden" Makefile.in
+  grep "^am\\.conf\\.${m}-triplet = \\\$(${m})$" Makefile.in
+  case $m in
+    build)
+      grep '^am\.conf\.host-triplet = *$' Makefile.in
+      grep '^am\.conf\.target-triplet = *$' Makefile.in
+      ;;
+    host)
+      grep '^am\.conf\.build-triplet = $(build)$' Makefile.in
+      grep '^am\.conf\.target-triplet = *$' Makefile.in
+      ;;
+    target)
+      grep '^am\.conf\.build-triplet = $(build)$' Makefile.in
+      grep '^am\.conf\.target-triplet = $(target)$' Makefile.in
+      ;;
+  esac
+done
+
+rm -rf autom4te.cache
+
+cat configure.tmpl - >configure.ac <<'END'
+AC_CANONICAL_HOST
+AC_CANONICAL_BUILD
+AC_CANONICAL_TARGET
+END
+
+$AUTOMAKE
+for m in host build target; do
+  grep "^$m = @address@hidden" Makefile.in
+  grep "^${m}_alias = @address@hidden" Makefile.in
+  grep "^am\.conf\.${m}-triplet = \$(${m})$" Makefile.in
+done
+
+:
-- 
1.7.12.rc0