The one-liner gcc buildPhase doesn't work anymore, so I'm using upstream
Makefile instead. The Makefile needs a tiny patch to work (not nixpkgs
specific).
Also fixup path to 'sox' and espeak-data/ (runtime deps) by providing
full paths.
TODO:
Uhm, seems like espeakedit still wants espeak-data/ in $HOME, even
thought I've told it to use $espeak/share/espeak-data. Have to contact
upstream to get this fixed.
Workaround:
cp -r $(nix-build -A espeak)/share/espeak-data ~
chmod +w ~/espeak-data
