_chsize_s

[John Z]

Would you consider adding a _chsize_s ?  When compiling the latest miniz I ran across this being used.

I'm also a bit confused about struct __stat64  vs. struct _stat64 (/GX option) miniz uses the double underscore. 

I modified the sources to make miniz compile and work under V13 with a few __POCC__ checks so no show stoppers - just throwing out there -

John Z

[TimoVJL]

check  _chsize64() and make a define for it.