"README" mentions "INSTALL" but this file doesn't exist in git checkout

Hi,
I'm attempting to get started with Postgres development. I checked out the
Postgres git sources from https://github.com/postgres/postgres. The README
notes:

See the file INSTALL for instructions on how to build and install
> PostgreSQL. That file also lists supported operating systems and
> hardware platforms and contains information regarding any other
> software packages that are required to build or run the PostgreSQL
> system.

Unfortunately this file doesn't exist in the sources.
Commit 0bcc2beb4a8e27c407da7d247083937261b60071 removed it, and the message
says it gets built as part of the "tarball scripts" now.

Given that people who have the git source are more likely to try to get
started building the source code, it may be helpful to provide more useful
information in the README, or a backup location to look?

Thanks for your help,
Kevin