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Diffstat (limited to 'm4/shell.m4')
-rw-r--r-- | m4/shell.m4 | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/m4/shell.m4 b/m4/shell.m4 new file mode 100644 index 0000000..a4b554d --- /dev/null +++ b/m4/shell.m4 @@ -0,0 +1,97 @@ +# Check for a working shell. + +# Copyright (C) 2000-2001, 2007, 2009-2016 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 3, 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, write to the Free Software +# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA +# 02111-1307, USA. + +# AC_PROG_SHELL +# ------------- +# Check for a working (i.e. POSIX-compatible) shell. +# Written by Paul Eggert <eggert@twinsun.com>, +# from an idea suggested by Albert Chin-A-Young <china@thewrittenword.com>. +AC_DEFUN([AC_PROG_SHELL], + [AC_MSG_CHECKING([for a POSIX-compliant shell]) + AC_CACHE_VAL(ac_cv_path_shell, + [ac_command=' + # Test the noclobber option, using the portable POSIX.2 syntax. + set -C + rm -f conftest.c + >conftest.c || exit + >|conftest.c || exit + !>conftest.c || exit + # Test that $(...) works. + test "$(expr 3 + 4)" -eq 7 || exit + ' + # Solaris 11 /bin/sh (AT&T Research) 93u 2011-02-08 has a file + # descriptor bug that breaks zgrep and is hard to test for + # directly. At some point $(...) is reading a pipe from the + # subshell, but the pipe is also open in the parent shell, so + # the read deadlocks. Prefer some other shell if available. + ac_maybe_solaris_sh_bug='test "${.sh.version}"' + + ac_cv_path_shell=no + + case $SHELL in + /*) + rm -f conftest.c + if ("$SHELL" -c "$ac_command") 2>/dev/null; then + "$SHELL" -c "$ac_maybe_solaris_sh_bug" 2>/dev/null || + ac_cv_path_shell=$SHELL + fi + esac + + case $ac_cv_path_shell in + no) + # Prefer shells that are more likely to be installed in the + # same place on all hosts of this platform. Therefore, prefer + # shells in /bin and /usr/bin to shells in the installer's + # PATH. Also, loop through PATH first and then through + # shells, since less-"nice" shells in /bin and /usr/bin are + # more likely to be installed than "nicer" shells elsewhere. + ac_break_if_good_shell=: + as_save_IFS=$IFS; IFS=: + for as_dir in /bin /usr/bin $PATH + do + IFS=$as_save_IFS + case $as_dir in + /*) + for ac_base in sh bash ksh sh5; do + rm -f conftest.c + if ("$as_dir/$ac_base" -c "$ac_command") 2>/dev/null; then + if "$as_dir/$ac_base" -c "$ac_maybe_solaris_sh_bug" 2>/dev/null + then + test "$ac_cv_path_shell" = no + else + ac_break_if_good_shell=break + : + fi && ac_cv_path_shell=$as_dir/$ac_base + $ac_break_if_good_shell + fi + done + $ac_break_if_good_shell + esac + done + rm -f conftest.c + esac]) + AC_MSG_RESULT($ac_cv_path_shell) + SHELL=$ac_cv_path_shell + if test "$SHELL" = no; then + SHELL=/bin/sh + AC_MSG_WARN([using $SHELL, even though it does not conform to POSIX]) + fi + if "$SHELL" -c "$ac_maybe_solaris_sh_bug" 2>/dev/null; then + AC_MSG_WARN([using $SHELL, even though it may have file descriptor bugs]) + fi + AC_SUBST(SHELL)]) |