Clean up some warnings

This makes the build output length drops from 1500 lines to 300 in MSVC
1) for our purposes they are equal, however it should be clear that there's no guarantee that on every platform there would be u32==unsigned
2) using u32 instead of unsigned suggests that there is a reason to have the variable be fixed-sized as 32 bits, which makes the code potentially confusing when there's actually no such reason.