[PD-dev] pd compiled for web with emscripten

[Claude Heiland-Allen]

Hi!

As a proof of concept I modified pure-data and libpd just enough to get 
it to compile with Emscripten and run some patches:

https://mathr.co.uk/empd/

Only -nogui mode.  You can make GUIs using SDL2 and OpenGL, or using 
other web APIs (HTML forms, SVG, etc).

Performance (provided you compile in Release mode) is about 2x worse 
than native in one of my tests.

Changes were mainly annoying rather than hard:
- Emscripten is stricter about calling function pointers with the 
correct type, this means pd_typedmess explodes from 6 cases to 60.
- I also needed to special-case pd_objectmaker in more places, because 
its methods have return values other than void.
- These type errors are only visible at runtime, so I may have missed 
some - please report.

Some other smaller fixes I may make pull-requests for soon.


Claude
-- 
https://mathr.co.uk