build: bootstrap overhaul
Put an end to the constant autoreconfs when switching branches. Use make to
determine when bootstrapping for xbmc and subprojects needs to happen
(hint: rarely).
bootstrapping can now be done in parallel, but I didn't obseve much (any?)
speed increase.
Also allows for easier skipping of reconfigures for minor/cosmetic configure.in
changes.
This should be transparent to users, other than the fact that it's much faster.
Same build procedure as always: ./bootstrap && ./configure && make
projects / vuplus_xbmc / commit