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-rw-r--r--m4/posix-shell.m463
1 files changed, 63 insertions, 0 deletions
diff --git a/m4/posix-shell.m4 b/m4/posix-shell.m4
new file mode 100644
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+++ b/m4/posix-shell.m4
@@ -0,0 +1,63 @@
+# Find a POSIX-conforming shell.
+
+# Copyright (C) 2007-2008 Free Software Foundation, Inc.
+
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Written by Paul Eggert.
+
+# If a POSIX-conforming shell can be found, set POSIX_SHELL and
+# PREFERABLY_POSIX_SHELL to it. If not, set POSIX_SHELL to the
+# empty string and PREFERABLY_POSIX_SHELL to '/bin/sh'.
+
+AC_DEFUN([gl_POSIX_SHELL],
+[
+ AC_CACHE_CHECK([for a shell that conforms to POSIX], [gl_cv_posix_shell],
+ [gl_test_posix_shell_script='
+ func_return () {
+ (exit [$]1)
+ }
+ func_success () {
+ func_return 0
+ }
+ func_failure () {
+ func_return 1
+ }
+ func_ret_success () {
+ return 0
+ }
+ func_ret_failure () {
+ return 1
+ }
+ subshell_umask_sanity () {
+ (umask 22; (umask 0); test $(umask) -eq 22)
+ }
+ test "[$](echo foo)" = foo &&
+ func_success &&
+ ! func_failure &&
+ func_ret_success &&
+ ! func_ret_failure &&
+ (set x && func_ret_success y && test x = "[$]1") &&
+ subshell_umask_sanity
+ '
+ for gl_cv_posix_shell in \
+ "$CONFIG_SHELL" "$SHELL" /bin/sh /bin/bash /bin/ksh /bin/sh5 no; do
+ case $gl_cv_posix_shell in
+ /*)
+ "$gl_cv_posix_shell" -c "$gl_test_posix_shell_script" 2>/dev/null \
+ && break;;
+ esac
+ done])
+
+ if test "$gl_cv_posix_shell" != no; then
+ POSIX_SHELL=$gl_cv_posix_shell
+ PREFERABLY_POSIX_SHELL=$POSIX_SHELL
+ else
+ POSIX_SHELL=
+ PREFERABLY_POSIX_SHELL=/bin/sh
+ fi
+ AC_SUBST([POSIX_SHELL])
+ AC_SUBST([PREFERABLY_POSIX_SHELL])
+])