init: ensure $ac_aux_dir is defined before being used

Since we use '$ac_aux_dir' to define '$am_aux_dir', we need
to ensure the former has been initialized before we try to
define the latter, otherwise the definition:

   am_aux_dir=`cd $ac_aux_dir && pwd`

will set '$am_aux_dir' to '$HOME', likely causing weird and
unexpected behaviours.

This change fixes automake bug#15981.

* m4/auxdir.m4 (AM_AUX_DIR_EXPAND): AC_REQUIRE expansion
of 'AC_CONFIG_AUX_DIR_DEFAULT'. Fix redundant comment and
AC_PREREQ, add extra quoting around '$ac_aux_dir'.
* t/auxdir-pr15981.sh: New test.
* t/auxdir-cc-pr15981.sh: Likewise.
* t/list-of-tests.mk (handwritten_TESTS): Add them.
* THANKS, NEWS: Update.
* bin/automake.in: Fix a harmless typo in comments, that
I happened to notice while writing this patch.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/t/auxdir-cc-pr15981.sh b/t/auxdir-cc-pr15981.sh
new file mode 100644
index 000000000..74157cbc1
--- /dev/null
+++ b/t/auxdir-cc-pr15981.sh
@@ -0,0 +1,57 @@
+#! /bin/sh
+# Copyright (C) 2014 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/>.
+
+# Test automake bug#15981: automake 1.14 may use $ac_aux_dir
+# before it is defined, leading to error messages such as:
+# "/bin/sh: /home/david/missing: No such file or directory"
+
+required=cc
+. test-init.sh
+
+cat > configure.ac <<END
+AC_INIT([$me], [0.0])
+AC_USE_SYSTEM_EXTENSIONS
+AM_INIT_AUTOMAKE([1.11 foreign])
+AC_CONFIG_FILES([Makefile])
+AC_SUBST([MISSING])
+AC_OUTPUT
+test -n "\${MISSING}"
+END
+
+echo 'int main (void) { return 0; }' > foo.c
+
+cat > Makefile.am <<'END'
+bin_PROGRAMS = foo
+
+# Without quotes around '--help' and with an empty $(MISSING), make might
+# strip the trailing '--', call Bash's 'help' builtin, and have this test
+# succeed spuriously.  Yes, that has happened in practice :-(
+test:
+	$(MISSING) '--help'
+END
+
+$ACLOCAL
+$AUTOCONF
+$AUTOMAKE
+
+./configure 2>stderr || { cat stderr >&2; exit 1; }
+cat stderr >&2
+$FGREP "missing" stderr && exit 1
+
+$MAKE all
+$MAKE test
+
+: