The current state of building C/C++ projects sucks.
ibt tries to make it better.
The ibt command is designed to be built by itself.
To get setup, there is a bit of a bootstrapping process:
# Build an initial ibt into build.strap/
$ script/strap.sh
# Use ibt to build itself
$ build.strap/ibtThe resulting build/ibt should now be ready.
When hacking on ibt,
it may be useful to run mv build build.stable from a working commit,
and running build.stable/ibt to build your changes.