Minor nits

Fixes a printf format warning: %zd can’t represent the full range of uint32_t (because it prints size_t, which is signed 32-bit). It might be cleaner to declare inpos as the same type as inputsize/outputsize instead…

Removes leading space for %d. The space is there to make room for a leading minus when the number is negative. This isn’t useful for the uncompressed size, which is always positive.

rm fails if the files don’t exist. rm -f always succeeds.

Removes CC line. You might want to add this for Windows, but please leave it out of the Linux options. Unix systems will default to the system compiler (usually /usr/bin/cc, which is linked to whatever is preferred on the system). This allows using Clang’s static analyzer.