[HarfBuzz] Compile issue with MSVC

[John Emmas]

I hope this is the right place for developer questions.

I just updated harbuzz from git (having last updated about a fortnight 
ago).  When I try building now with MSVC it gives me the following 
errors when I try to compile 'hb-ot-shape-complex-use.cc'

     Compiling... hb-ot-shape-complex-use.cc
     hb-ot-shape-complex-use-machine.rl(136) : error C2065: 
'consonant_cluster' : undeclared identifier
     hb-ot-shape-complex-use-machine.rl(137) : error C2065: 
'vowel_cluster' : undeclared identifier

I couldn't see anything obviously wrong so I went back to the original 
version 1.2.7 (from 2nd May 2016) and it still builds fine.  
'hb-ot-shape-complex-use.cc' has changed in the past couple of weeks - 
but so have some of the files it depends on (so it's all a bit 
convoluted).  I just wondered if anyone can take a guess at what might 
be wrong?  For example is there something I need to #define now (which 
wasn't needed previously?)

BTW - my internet access will be very poor for the next few days, so 
apologies in advance if I'm a bit slow in responding.  Many thanks,

John Emmas