PKGBUILD: add dependencies

For now, we *require* everything.

We _could_ modify the build system to exclude modules whose
dependencies haven't been met. That would allow us to make some of the
dependencies optional.

PKGBUILD

@@ -1,12 +1,25 @@
 pkgname=f00bar
-pkgver=$(git describe --always)
+pkgver=0.9.r1.g383e031
 pkgrel=1
 pkgdesc="Simplistic and highly configurable status panel for X"
 arch=('x86_64')
 url=https://gitlab.com/dnkl/f00bar
 license=(mit)
+depends=(
+  'libxcb' 'xcb-util' 'xcb-util-cursor'
+  'freetype2' 'fontconfig' 'cairo'
+  'libyaml'
+  'alsa-lib'
+  'libsystemd'
+  'json-c'
+  'libmpdclient')
+optdepends=('xcb-util-errors: better X error messages')
 source=()
 
+pkgver() {
+  git describe --tags --long | sed 's/^v//;s/\([^-]*-g\)/r\1/;s/-/./g'
+}
+
 build() {
   cmake -G Ninja -DCMAKE_BUILD_TYPE=MinSizeRel -DCMAKE_INSTALL_PREFIX=/usr ../
   ninja