Most users who realize that INSTALL files still exist should simply
follow the directions at
https://support.torproject.org/little-t-tor/getting-started/installing/#source

If you got the source from git, run "./autogen.sh", which will
run the various auto* programs. Then you can run ./configure, and
refer to the above instructions.

If it doesn't build for you:

  If you have problems finding libraries, try
    CPPFLAGS="-I/usr/local/include" LDFLAGS="-L/usr/local/lib" \
    ./configure
  or
    ./configure --with-libevent-dir=/usr/local
  rather than simply ./configure.

If you are on an Apple Silicon you probably want to invoke ./configure with the
CPPFLAGS and LDFLAGS as above, except that you probably need to use
/opt/homebrew/include and /opt/homebrew/lib instead of /usr/local.
