Add variable parsing in $"..." and fix several mismatches with bash.

* Makefile.util.def (grub_script_gettext): New test.
	* grub-core/script/execute.c (parse_string): New function.
	(gettext_append): Likewise.
	(grub_script_arglist_to_argv): Use gettext_append.
	* grub-core/script/yylex.l: Fix slash and newline handling in $"...".
	* tests/grub_script_gettext.in: New file.

tests/grub_script_gettext.in

@@ -0,0 +1,69 @@
+#! @builddir@/grub-shell-tester
+#
+# Copyright (C) 2010,2012  Free Software Foundation, Inc.
+#
+# GRUB 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 of the License, or
+# (at your option) any later version.
+#
+# GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
+
+echo $"foo"
+echo $"foo   bar"
+
+echo -n $"foo"
+
+echo -e $"foo\nbar"
+
+echo -n -e $"foo\nbar"
+
+x=5
+echo $"$x"
+echo $"\x\\y\$x$x\\$xx${x}x\"$x\""
+
+echo $"$"
+echo $"$,x"
+
+echo $"one
+"
+echo $"one
+\""
+echo $"one
+two"
+
+echo one$"two
+"three
+echo one$"two
+\""three
+echo one$"two
+\"three\"
+four"
+
+echo $"one\
+"
+echo $"one\
+\""
+echo $"one\
+two"
+
+echo one$"two\
+"three
+echo one$"two\
+\""three
+echo one$"two\
+\"three\"\
+four"
+
+if test -n "$grubshell"; then insmod regexp; fi
+
+echo $"*"
+
+foo="*"
+echo $"$foo"