Also pull in allegro5 platform files.

allegro5/Makefile

@@ -34,6 +34,8 @@ package:
 	cp -prv allegro5/include/allegro5/internal/aintern_bitmap.h out/opt/cppse/build/allegro5/include/allegro5/internal/aintern_bitmap.h
 	# since above file also includes others, let's just sync the entire internal dir
 	cp -prv allegro5/include/allegro5/internal/* out/opt/cppse/build/allegro5/include/allegro5/internal/
+	# somewhere also platform became needed, let's pull those in as well
+	cp -prv allegro5/include/allegro5/platform/* out/opt/cppse/build/allegro5/include/allegro5/platform/
 	rm -rf allegro5_1.0_amd64.deb
 	docker run -v "$$(pwd):/src/" rayburgemeestre/fpm-ubuntu:18.04 fpm -s dir -t deb -n allegro5 --license MPL2 --maintainer "Ray Burgemeestre <ray@cppse.nl>" --description "allegro5 - build dependency" --url "https://github.com/liballeg/allegro5.git" --deb-generate-changes -C /src/out