Add Valgrind to CI

* Also pass `$*` to `configure` when invoking `ci-build.sh`, so one can
  e.g. run `./ci-build.sh --without-xscreensaver`

Signed-off-by: Steffen Jaeckel <s@jaeckel.eu>

Dockerfile.arch

@@ -28,6 +28,7 @@ RUN pacman -Syu --noconfirm && pacman -S --needed --noconfirm \
   python \
   wget \
   sqlite \
+  valgrind \
   gdk-pixbuf2 \
   qrencode