Bootstrapping from binary blob shipped in the source package

[Florian Weimer <fw@deneb.enyo.de>]

Some packages (notably compilers) avoid cyclic build dependencies by
shipping some sort of pre-compiled blob in the source package.  This
blob is then used to compile the package.

Does this fullfil the requirement that packages in main must be built
from source code?

The alternative would be a cyclic build dependency, like the one we have
for GCC, binutils, libc etc.  A potential issue is that if upstream
breaks self-compilation, a manual upload on all affected architectures
is required.