dev: initial environment

fedora, centos and ubuntu

* fewer layers
* systemd-dev
* basic pieces for building docker everytime
* centos updates
* better automated build

gccgo/Makefile

@@ -0,0 +1,14 @@
+
+NAME := docker.usersys/$(USER)/gccgo
+DOCKER := $(shell which docker)
+
+all: build
+
+build: .build
+
+.build: Dockerfile
+	$(DOCKER) build -t $(NAME) . && touch $@
+
+clean:
+	rm -f .build $(wildcard *~)
+