ttcn3: colorize compiler output

Attach a tty to the docker container while building the testsuite, as
this is what "should_colorize()" checks for.

Related: b3dca57db9
Change-Id: I6d3c9e1e82b1cf4384b4abd3f1eed072d8fe6fde

ttcn3/ttcn3.sh

@@ -247,8 +247,10 @@ build_testsuite() {
 	# since we will run it inside docker later too.
 	local hacks="${DIR_OSMODEV}/src/osmo-ttcn3-hacks"
 
+	# -t: add a tty, so we get color output from the compiler
 	docker run \
 		--rm \
+		-t \
 		-v "$hacks:/osmo-ttcn3-hacks" \
 		"$(get_testsuite_image)" \
 		sh -exc "