builtin-grep: workaround for non GNU grep.

diff --git a/t/t6000lib.sh b/t/t6000lib.sh
index 01f796e9c827aff02c3161ac940626dd4d8edb9b..c6752af48e04993e3ed3efebf288ffa86d02633a 100755 (executable)
--- a/t/t6000lib.sh
+++ b/t/t6000lib.sh
@@ -51,7 +51,12 @@ as_author()
 
        export GIT_AUTHOR_EMAIL="$_author"
        "$@"
-        export GIT_AUTHOR_EMAIL="$_save"
+       if test -z "$_save"
+       then
+               unset GIT_AUTHOR_EMAIL
+       else
+               export GIT_AUTHOR_EMAIL="$_save"
+       fi
 }
 
 commit_date()