Add target to create a local PKGBUILD to install .deb on Arch

pacman target is somewhat broken, so let's do it similarly like the
official AUR package for local installs.

.gitignore

@@ -1,2 +1,3 @@
 release.mk
 /release
+/local-pkgbuild

Makefile

@@ -1,4 +1,4 @@
-.PHONY: all setup web desktop desktop-common linux windows windows-portable
+.PHONY: all setup web desktop desktop-common linux debian pacman local-pkgbuild local-pkgbuild-install windows windows-portable
 .PHONY: web-release debian-release pacman-release windows-setup-release windows-unpacked-release windows-portable-release windows-release release
 .PHONY: clean
 
@@ -67,6 +67,12 @@ windows: desktop-common
 windows-portable: desktop-common
 	$(YARN) --cwd element-desktop run build64windows-portable
 
+local-pkgbuild: debian
+	./create_local_pkgbuild.sh $(VERSION) $(DESKTOP_APP_NAME) $(PRODUCT_NAME) $(OUT_DEB64)
+
+local-pkgbuild-install: local-pkgbuild
+	cd local-pkgbuild; makepkg --install
+
 web-release: web
 	mkdir -p $(CURRENT_RELEASE_DIR)
 	cp $(OUT_WEB) $(CURRENT_RELEASE_DIR)
@@ -105,3 +111,4 @@ clean:
 	$(YARN) --cwd element-desktop clean
 	rm -f element-desktop/webapp
 	rm -rf element-web/dist
+	rm -rf local-pkgbuild

create_local_pkgbuild.sh

@@ -0,0 +1,42 @@
+#!/bin/sh
+
+set -e
+
+mydir="$(dirname "$(realpath "$0")")"
+cd "$mydir"
+
+version="$1"
+appName="$2"
+productName="$3"
+debOut="$4"
+
+template_dir="local-pkgbuild-template"
+out_dir="local-pkgbuild"
+
+if [ -z "$version" ] || [ -z "$appName" ] || [ -z "$productName" ] || [ -z "$debOut" ]; then
+    echo "Usage: $0 version appName productName debOut"
+    exit 1
+fi
+
+debName="$(basename "$debOut")"
+
+rm -rf "$out_dir"
+mkdir "$out_dir"
+
+setup_file() {
+    local file="$1"
+    local outfile="$2"
+    if [ -z "$outfile" ]; then
+        local outfile="$file"
+    fi
+    cat "$template_dir/$file" \
+        | sed "s|---version---|$version|g" \
+        | sed "s|---appName---|$appName|g" \
+        | sed "s|---productName---|$productName|g" \
+        | sed "s|---debName---|$debName|g" \
+        > "$out_dir/$outfile"
+}
+
+setup_file PKGBUILD
+setup_file schildichat-desktop.sh "$appName.sh"
+ln -r -s "$debOut" "$out_dir/$debName"

local-pkgbuild-template/PKGBUILD

@@ -0,0 +1,25 @@
+# Maintainer: su-ex <codeworks@supercable.onl>
+# Maintainer: SpiritCroc <aur@spiritcroc.de>
+# Contributor: David Mehren <david.mehren@udo.edu>
+
+pkgname=---appName----git
+_pkgver=---version---
+pkgver=${_pkgver//-/.}
+pkgrel=1
+pkgdesc="SchildiChat is a Matrix client based on Element with a more traditional instant messaging experience."
+arch=('x86_64')
+url="https://schildi.chat"
+license=('Apache')
+depends=('sqlcipher')
+provides=('---appName---')
+conflicts=('---appName---')
+source=("---debName---"
+        "---appName---.sh")
+sha256sums=('SKIP'
+            'SKIP')
+
+package() {
+  msg2 "Extracting the data.tar.xz..."
+  bsdtar -xf data.tar.xz -C "$pkgdir/"
+  install -Dm755 "${srcdir}"/---appName---.sh "${pkgdir}"/usr/bin/---appName---
+}

local-pkgbuild-template/schildichat-desktop.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+exec "/opt/---productName---/---appName---" "$@"