[Radiant] freezing edge submodules and git

[Simon]

I've been getting lots of challenging messages from Git about
submodules, like "No submodule mapping found in .gitmodules for path
'vendor/radiant'" when I try to commit changes using Git 1.7.3.3. Is
there a step I'm missing in installing the edge version which would
allow me to skip adding and updating each submodule in vendor/radiant
separately? Do I need the granularity of having both a project and a
vendor/Radiant repository?