[zlib] Some organizational changes.

We now first apply zlib's `zlib2ansi` script, then FreeType's patch file.

* src/gzip/README.freetype: Updated.

* patches/0001-zlib-Fix-zlib-sources-to-compile-for-FreeType.patch: Renamed
* patches/freetype-zlib.diff: This.
Clean up description, then regenerate it as follows:

  - Copy unmodified files from `zlib` repository.
  - Run `zlib2ansi` script.
  - Run `git diff -R > patches/freetype-zlib.diff.new`.
  - Insert patch description of old diff file, then replace old diff with
    new diff file.
4 files changed