mesa; add get-extra-pick-list.sh script into bin/

This is a very rudimentary script that checks if any of the applied
cherry-picks have been referenced (fixed?) by another patch. With the
latter either missing the stable tag or hasn't yet been picked.

Cc: "11.1 11.2" <mesa-stable@lists.freedesktop.org>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>

bin/get-extra-pick-list.sh

@@ -0,0 +1,35 @@
+#!/bin/sh
+
+# Script for generating a list of candidates which fix commits that have been
+# previously cherry-picked to a stable branch.
+#
+# Usage examples:
+#
+# $ bin/get-extra-pick-list.sh
+# $ bin/get-extra-pick-list.sh > picklist
+# $ bin/get-extra-pick-list.sh | tee picklist
+
+# Use the last branchpoint as our limit for the search
+# XXX: there should be a better way for this
+latest_branchpoint=`git branch | grep \* | cut -c 3-`-branchpoint
+
+# Grep for commits with "cherry picked from commit" in the commit message.
+git log --reverse --grep="cherry picked from commit" $latest_branchpoint..HEAD |\
+	grep "cherry picked from commit" |\
+	sed -e 's/^[[:space:]]*(cherry picked from commit[[:space:]]*//' -e 's/)//' |\
+	cut -c -8 |\
+while read sha
+do
+	# Check if the original commit is referenced in master
+	git log -n1 --pretty=oneline --grep=$sha $latest_branchpoint..origin/master |\
+		cut -c -8 |\
+	while read candidate
+	do
+		# Check if the potential fix, hasn't landed in branch yet.
+		found=`git log -n1 --pretty=oneline --reverse --grep=$candidate $latest_branchpoint..HEAD |wc -l`
+		if test $found = 0
+		then
+			echo Commit $candidate might need to be picked, as it references $sha
+		fi
+	done
+done