manibuilder/debian: Allow to install additional packages

Change-Id: I276b2e7da21f934c9e114567a40820f095a7162b
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.sourcearcade.org/c/flashprog/+/364
diff --git a/util/manibuilder/Dockerfile.debian b/util/manibuilder/Dockerfile.debian
index 1835941..111e8e8 100644
--- a/util/manibuilder/Dockerfile.debian
+++ b/util/manibuilder/Dockerfile.debian
@@ -2,12 +2,14 @@
 
 FROM manibase
 
+ARG ADDITIONAL_PACKAGES=
 RUN \
 	useradd -p locked -m mani && \
 	apt-get -qq update && \
 	apt-get -qq upgrade && \
 	apt-get -qqy install gcc make git doxygen ccache pkg-config meson \
-		libpci-dev libftdi1-dev libusb-1.0-0-dev && \
+		libpci-dev libftdi1-dev libusb-1.0-0-dev \
+		${ADDITIONAL_PACKAGES} && \
 	{ apt-get -qqy install libjaylink-dev libgpiod-dev || true; } && \
 	apt-get clean