Add PKGBUILD

Thanks @ha:matrix.org for the initial script

dist/AUR/PKGBUILD

+# Maintainer: Konstantinos Sideris <siderisk at auth dot gr>
+
+pkgname=nheko-git
+pkgver=0.1.0.e78e43c86a39
+pkgrel=1
+pkgdesc="Desktop client for the Matrix protocol"
+arch=('i686' 'x86_64')
+
+url="https://github.com/mujx/nheko"
+license=('GPL3')
+
+depends=('qt5-base')
+makedepends=('git' 'cmake' 'gcc' 'fontconfig')
+
+source=($pkgname::git+https://github.com/mujx/nheko.git)
+md5sums=('SKIP')
+
+pkgver() {
+    cd "$pkgname"
+    printf "0.1.0.%s" "$(git rev-parse --short HEAD)"
+}
+
+build() {
+    cd "$pkgname"
+    cmake -H. -Bbuild -DCMAKE_BUILD_TYPE=Release
+    make -C build -j2
+}
+
+package() {
+	# Creating needed directories
+	install -dm755 "$pkgdir/usr/bin"
+	install -dm755 "$pkgdir/usr/share/pixmaps/"
+	install -dm755 "$pkgdir/usr/share/applications/"
+
+	# Program
+    install -Dm755 "$pkgname/build/nheko" "$pkgdir/usr/bin/nheko"
+
+    # Desktop launcher
+	install -Dm644 "$srcdir/$pkgname/resources/nheko-256.png" "$pkgdir/usr/share/pixmaps/nheko.png"
+	install -Dm644 "$srcdir/$pkgname/resources/nheko.desktop" "$pkgdir/usr/share/applications/nheko.desktop"
+
+    # Icons
+    local icon_size icon_dir
+	for icon_size in 16 32 48 64 128 256 512; do
+		icon_dir="$pkgdir/usr/share/icons/hicolor/${icon_size}x${icon_size}/apps"
+		install -d "$icon_dir"
+		install -m644 "$srcdir/$pkgname/resources/nheko-${icon_size}.png" "$icon_dir/nheko.png"
+	done
+}

resources/nheko.desktop

+[Desktop Entry]
+Name=nheko
+Version=0.1
+Comment=Desktop client for Matrix
+Exec=nheko
+Icon=nheko
+Type=Application
+Categories=Network;InstantMessaging;Qt;
+Encoding=UTF-8
+StartupWMClass=nheko
+Terminal=false