Add tooling to generate PKGBUILD after cargo publish

PKGBUILD.in

@@ -0,0 +1,33 @@
+# Maintainer: Gergő Sályi <salyigergo94@gmail.com>
+pkgname=multibg-sway
+pkgver=@pkgver@
+pkgrel=1
+pkgdesc='Set a different wallpaper for the background of each Sway workspace'
+arch=('x86_64' 'i686' 'pentium4' 'armv7h' 'aarch64')
+url="https://github.com/gergo-salyi/multibg-sway"
+license=('MIT' 'Apache')
+depends=('gcc-libs' 'glibc')
+makedepends=('cargo')
+optdepends=('sway: window manager to set the wallpapers with')
+source=("$pkgname-$pkgver.tar.gz::https://static.crates.io/crates/$pkgname/$pkgname-$pkgver.crate")
+sha256sums=('@sha256sum@')
+
+prepare() {
+    cd "$pkgname-$pkgver"
+    export RUSTUP_TOOLCHAIN=stable
+    cargo fetch --locked --target "$(rustc -vV | sed -n 's/host: //p')"
+}
+
+build() {
+    cd "$pkgname-$pkgver"
+    export RUSTUP_TOOLCHAIN=stable
+    export CARGO_TARGET_DIR=target
+    cargo build --frozen --release
+}
+
+package() {
+    cd "$pkgname-$pkgver"
+    install -Dm0755 -t "$pkgdir/usr/bin/" "target/release/$pkgname"
+    install -Dm644 "README.md" "$pkgdir/usr/share/doc/${pkgname}/README.md"
+    install -Dm644 "LICENSE-MIT" "$pkgdir/usr/share/licenses/${pkgname}/LICENSE-MIT"
+}

scripts/pkgbuild.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+set -euo pipefail
+
+if [[ "$(head -2 Cargo.toml)" != '[package]
+name = "multibg-sway"' ]]; then
+    echo 'Not in crate root'
+    exit 1
+fi
+
+version=$(cargo pkgid | cut -d '#' -f2)
+crate="target/package/multibg-sway-$version.crate"
+sum=$(sha256sum "$crate" | cut -d ' ' -f1)
+
+if [[ PKGBUILD -nt "$crate" ]]; then
+    echo 'Nothing to do'
+    exit 1
+fi
+
+sed -e "s/@pkgver@/$version/" -e "s/@sha256sum@/$sum/" < PKGBUILD.in > PKGBUILD