retroarch-release.sh: Added script to create RetroArch release tarballs.

This script will create a .zip, .tar.gz and .tag.xz from the most
recent RetroArch release tag.

retroarch-release.sh

@@ -0,0 +1,39 @@
+#!/bin/sh
+# vim: set ts=3 sw=3 noet ft=sh : bash
+# RetroArch packaging script
+
+PRGNAM=RetroArch
+SRCNAM="$(printf %s $PRGNAM | tr '[:upper:]' '[:lower:]')"
+TMP=${TMP:-/tmp/libretro}
+
+set -eu
+
+# Ensure a clean and fully updated repo
+if [ -d $SRCNAM ]; then
+	rm -rf -- $SRCNAM
+	./libretro-fetch.sh $SRCNAM
+fi
+
+COMMIT="$(git --work-tree=$SRCNAM --git-dir=$SRCNAM/.git describe --abbrev=0 \
+	--tags)"
+VERSION="$(printf %s $COMMIT | tr -d v)"
+
+trap 'rm -rf -- $TMP/$PRGNAM-$VERSION; exit 0' EXIT INT
+
+# Don't alter the original cloned repo
+mkdir -p -- "$TMP"
+rm -rf -- "$TMP/$PRGNAM-$VERSION"
+cp -a $SRCNAM "$TMP/$PRGNAM-$VERSION"
+
+# Checkout the last release tag
+git --work-tree="$TMP/$PRGNAM-$VERSION" --git-dir="$TMP/$PRGNAM-$VERSION/.git" \
+	checkout "$COMMIT"
+
+# Remove .git directories and files
+find "$TMP/$PRGNAM-$VERSION" -name ".git*" | xargs rm -rf
+
+cd -- "$TMP"
+
+# Create .zip and .tar.xz release tarballs.
+zip -r "$PRGNAM-$VERSION.zip" "$PRGNAM-$VERSION"
+tar cf - "$PRGNAM-$VERSION" | xz -c9 - > "$PRGNAM-$VERSION.tar.xz"