build: check compilation of each commit

Inspired by Rust Lightning's GH action :)

scripts/check-each-commit.sh

@@ -0,0 +1,15 @@
+#!/bin/bash
+if [[ "$1" = "" ]]; then
+	echo "USAGE: $0 remote/head_branch"
+	echo "eg $0 upstream/master"
+	exit 1
+fi
+
+set -e
+set -x
+
+if [[ "$(git log --pretty="%H %D" | grep "^[0-9a-f]*.* $1")" = "" ]]; then
+	echo "It seems like the current checked-out commit is not based on $1"
+	exit 1
+fi
+git rebase --exec scripts/check-commit.sh $1