Fixing warnings in utils/metadata when building under Windows/Cygwin

Builds under Cygwin and Linux with these changes
That sounds good to me. 

I was having a Google around though and I see there's a project that attempts to define stdint.h and inttypes.h for VS here

https://code.google.com/p/msinttypes/

Assuming that the (BSD) license is acceptable would be be worth us considering pulling these in for MSVC for completeness?