3 on commit to submodule:
7 superrepo heads are dev, prod
8 on commit to superrepo:
9 for each changed submodule revision:
10 (as optimization: if same commit already in dev, just reprepro move)
11 try to build submodule
12 if fail, abort -- whole commit, probably; else
13 tag submodule with version
14 upload to dev/prod respectively
18 This makes a long pre-receive process. Is that cool?
19 Probably is the right thing.