graphics/fotoxx: the port had been updated to version 23.32

- Mute the `-Wwritable-strings' warnings (ISO C++11 does not allow
  conversion from string literal to `char *') for the time being:
  there are tons of them and they clobber the build log, making it
  hard to look for more important warnings and errors
- While here, make `pkg-plist' better sorted against LC_COLLATE=C