>>31
CMake is a cross platform
makefile generator system. You can use CMake to
generate GNU Make compliant
makefiles.
First, you write your project's build configuration using CMake's special language. Next, you use the CMake program to
generate makefiles from your CMake build config. Finally, you use your native build system to actually build the software.
You use CMake's system to generate makefiles because IMO, it's far easier to write powerful build configurations using CMake's system as compared to writing your build configurations in their native language. The fact that CMake supports multiple make systems also makes it convenient to write a single build configuration that will work on the supported make systems.
>>32
Compare the compression ratios for 7-zip's format with other compression formats. You'll find 7-zip's ratios will match the best of them.