grub-2.0: fix bash completion script

pkgs/tools/misc/grub/2.0x.nix

···
            -e "s|/usr/src/unifont.bdf|$PWD/unifont.bdf|g"
     '';
 
+  patches = [ ./fix-bash-completion.patch ];
+
   configureFlags =
     let arch = if stdenv.system == "i686-linux" then "i386"
                else if stdenv.system == "x86_64-linux" then "x86_64"

pkgs/tools/misc/grub/fix-bash-completion.patch

···
+diff -ubr grub-2.00-orig/util/bash-completion.d/grub-completion.bash.in grub-2.00/util/bash-completion.d/grub-completion.bash.in
+--- grub-2.00-orig/util/bash-completion.d/grub-completion.bash.in	2012-10-16 19:02:36.342733957 +0200
++++ grub-2.00/util/bash-completion.d/grub-completion.bash.in	2012-10-16 19:04:48.262733941 +0200
+@@ -17,6 +17,12 @@
+ # along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ # bash completion for grub
+ 
++have()
++{
++    unset -v have
++    _have $1 && have=yes
++}
++
+ __grub_dir() {
+     local i c=1 boot_dir
+ 
+@@ -479,6 +485,7 @@
+ have ${__grub_script_check_program} && \
+  complete -F _grub_script_check -o filenames ${__grub_script_check_program}
+ 
++unset -f have
+ 
+ # Local variables:
+ # mode: shell-script