build: Add 'pre-inst-env' wrapper script

This script allows someone building Automake from source to easily run
'automake' and 'aclocal' without having to install it or knowing the
existence of "wrapped" scripts in "bin" directory.

* pre-inst-env.in: New script.
* configure.ac: Generate 'pre-inst-env' at configure time.
* Makefile.am (nodist_noinst_SCRIPTS, CLEANFILES): Add it.

3 files changed, 37 insertions, 0 deletions

diff --git a/Makefile.am b/Makefile.am
index 65787e030..bdcafd933 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -69,6 +69,10 @@ generated_file_finalize = $(AM_V_at) \
   fi; \
   chmod a-w $@-t && mv -f $@-t $@
 
+# Wrapper for the build environment.
+nodist_noinst_SCRIPTS += pre-inst-env
+CLEANFILES += $(noinst_SCRIPTS)
+
 # For some tests or targets, we need to have the just-build automake and
 # aclocal scripts avaiable on PATH.
 extend_PATH = \
diff --git a/configure.ac b/configure.ac
index c9c257b37..e936e9e00 100644
--- a/configure.ac
+++ b/configure.ac
@@ -580,6 +580,7 @@ AC_SUBST([EXEEXT])
 AC_CONFIG_FILES([Makefile])
 AC_CONFIG_LINKS([GNUmakefile:GNUmakefile])
 
+AC_CONFIG_FILES([pre-inst-env], [chmod +x pre-inst-env])
 AC_CONFIG_FILES([bin/aclocal-${APIVERSION}:bin/wrap-aclocal.in],
                 [chmod +x bin/aclocal-${APIVERSION}],
                 [APIVERSION=$APIVERSION])
diff --git a/pre-inst-env.in b/pre-inst-env.in
new file mode 100644
index 000000000..1599c7b5d
--- /dev/null
+++ b/pre-inst-env.in
@@ -0,0 +1,32 @@
+#! /bin/sh
+# Copyright © 2017 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+abs_top_srcdir="@abs_top_srcdir@"
+abs_top_builddir="@abs_top_builddir@"
+
+sep='@PATH_SEPARATOR@';
+
+PERL5LIB="$abs_top_builddir/lib/${sep}$abs_top_srcdir/lib/${PERL5LIB:+${sep}}$PERL5LIB"
+export PERL5LIB
+
+PATH="$abs_top_builddir/bin${sep}$PATH"
+export PATH
+
+# Trigger the use of local modules.
+AUTOMAKE_UNINSTALLED=1
+export AUTOMAKE_UNINSTALLED
+
+exec "$@"