The table can now compile independently too.  If we cannot make it work
on MSVC, we can always generate the data and distribute it.

The code now compiles cleanly with:

gcc -c -xc -std=c99 -Werror -pedantic hb-ot-shape-complex-arabic-win1256.hh
g++ -c -xc -std=c++1x -Werror -pedantic hb-ot-shape-complex-arabic-win1256.hh

See:
https://github.com/behdad/harfbuzz/commit/a97f537cec209649302899975d76ca2b2661da7a#commitcomment-7218736