Rework the builder targets so we may use different remotes

Now, in order to set up the builder at a given remote @ commit , we
will want to make

     ${docker_src}/built/openwrt-builder-remote_commit.sentinel

... and then use the openwrt-builder-remote_commit image as a base.

New remotes can / should be added to openwrt-remotes.txt. Honestly
this oughta have been under the openwrt dir but, eh.

Makefile

@@ -17,6 +17,17 @@ ${docker_src}/built/debian_10.sentinel:
 
 ${docker_src}/built/openwrt-builder-%.sentinel: \
  ${docker_src}/openwrt-builder-commit.dockerfile \
- ${docker_src}/built/openwrt-builder.sentinel
-	cd ${docker_src}; docker build -f $< --build-arg=commit=$* --tag openwrt-builder-$* .; \
+ ${docker_src}/built/openwrt-builder.sentinel \
+ ${docker_src}/openwrt-remotes.txt
+	cd ${docker_src}; \
+	rev=$*; \
+	if [ "$rev" != "$${rev%_*}" ]; then \
+		remote=$(shell echo $* | cut -d_ -f1); \
+		commit=$(shell echo $* | cut -d_ -f2); \
+		remoteurl=$(shell echo $* | cut -d_ -f1 | xargs -I{} grep -e "^{}" ${docker_src}/openwrt-remotes.txt | cut -d '	' -f2); \
+		docker build -f $< --build-arg=remote="$$remote" --build-arg=commit="$$commit" --build-arg=remoteurl="$$remoteurl" --tag openwrt-builder-$* .; \
+	else \
+		commit=$(shell echo $*); \
+		docker build -f $< --build-arg=commit="$$commit" --tag openwrt-builder-$* . ; \
+	fi; \
 	touch $@;

openwrt-builder-commit.dockerfile

@@ -1,10 +1,17 @@
 FROM openwrt-builder
 
-ARG commit
+ARG remote="origin"
+
+ARG remoteurl="https://git.laboratoryb.org/hurricos/openwrt-mirror"
+
+ARG commit="master"
 
 RUN cd ${openwrt_dir} \
-    && git pull origin master \
-    && git checkout ${commit} \
+    && ( git remote add ${remote} ${remoteurl} --tags || true )
+
+RUN cd ${openwrt_dir} \
+    && git fetch --all \
+    && git checkout ${remote}/${commit} \
     && ./scripts/feeds update -a \
     && ./scripts/feeds install -a
 

openwrt-remotes.txt

@@ -0,0 +1,2 @@
+mirror	https://git.laboratoryb.org/hurricos/openwrt-mirror
+local	https://git.laboratoryb.org/hurricos/openwrt