gcc: add args to common/builder.nix, split up script into phases

This commit adds arguments to `builder.nix`, making it a callable
function, and splits up the single massive shell script into
separate attributes for each phase.  It also drops the first two
lines and the last line because these are part of the default
builder.

All script lines which were not part of a phase function have been
moved into `preUnpack` since this is the first phase that runs.
Subsequent commits will move parts of this to more sensible
locations.

0 files changed, 0 insertions, 0 deletions