Fixed warning in MSVC by prefixing the macros, MEM_FREE is already defined in winnt.h.
Fixed unsigned/signed mismatch warning.
Fixed unreferenced variables/label warnings in MSVC.
Fixed MSVC warning about different types for formal and actual parameter.
Fixed MSVC warning about unreferenced local variable.
Fixed unreferenced local variable warning in MSVC.
Fixed warning in MSVC: 'getpid' undefined; assuming extern returning int.
Fixed warning in MSVC: 'different types for formal and actual parameter'.
Fixed warning in MSVC: 'unreferenced local variable'.
Fixed warning in MSVC: 'unreferenced local variable'.
Removed an unused variable from the code, fixes a warning in MSVC.
Fixed warnings in MSVC: 'unreferenced local variable'.
Fixed warning in MSVC: 'void' function returning a value.
Fixed warning in MSVC: 'different types for formal and actual parameter'.
Fixed warning in MSVC: 'unreferenced local variable'.
Merge pull request #1084 from tritao/msvc-warnings

MSVC warning fixes