libgwater.m4: Require pkg-config

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
libgwater.m4: Fix libtool detection

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
template.mk: Make each component to depend on config header

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
mpd: Handle more errors

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
libgwater.m4: Fix canonalized component name

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Add ALSA Mixer GSource

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>