Teach git-pull to pass -X<option> to git-merge

This needs the usual sq then eval trick to allow IFS characters
in the option.

Signed-off-by: Avery Pennarun <apenwarr@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/git-pull.sh b/git-pull.sh
index bfeb4a0..6d961b6 100755
--- a/git-pull.sh
+++ b/git-pull.sh
@@ -18,6 +18,7 @@
 
 strategy_args= diffstat= no_commit= squash= no_ff= ff_only=
 log_arg= verbosity=
+merge_args=
 curr_branch=$(git symbolic-ref -q HEAD)
 curr_branch_short=$(echo "$curr_branch" | sed "s|refs/heads/||")
 rebase=$(git config --bool branch.$curr_branch_short.rebase)
@@ -62,6 +63,18 @@
 		esac
 		strategy_args="${strategy_args}-s $strategy "
 		;;
+	-X*)
+		case "$#,$1" in
+		1,-X)
+			usage ;;
+		*,-X)
+			xx="-X $2"
+			shift ;;
+		*,*)
+			xx="$1" ;;
+		esac
+		merge_args="$merge_args$xx "
+		;;
 	-r|--r|--re|--reb|--reba|--rebas|--rebase)
 		rebase=true
 		;;
@@ -216,7 +229,7 @@
 
 merge_name=$(git fmt-merge-msg $log_arg <"$GIT_DIR/FETCH_HEAD") || exit
 test true = "$rebase" &&
-	exec git-rebase $diffstat $strategy_args --onto $merge_head \
+	exec git-rebase $diffstat $strategy_args $merge_args --onto $merge_head \
 	${oldremoteref:-$merge_head}
-exec git-merge $diffstat $no_commit $squash $no_ff $ff_only $log_arg $strategy_args \
+exec git-merge $diffstat $no_commit $squash $no_ff $ff_only $log_arg $strategy_args $merge_args \
 	"$merge_name" HEAD $merge_head $verbosity