Log Message:
PC6001VX: update to 3.2.0.

pkgsrc changes:

- README.html is no longer in the distribution tarball
  so make it optional and generate it using asciidoc and
  source-highlight.

Upstream changes (from README.adoc):

.3.2.0 2019/9/14
* Compatible ROM implemented by AKIKAWA Hisashi is now built
  in the emulator. Now the emulator is bootable without genuine ROM.
* Fixed timer interrupt interval on SR models.(temporal fix)
* Assigned Alt+F9/F10 hotkey to state save/load.
* Dropped "Patch the ROM" setting. (Because it made JOYSTICK2 unusable.)