Null Void

pkg-config was designed for unix os. And of course it more difficult to use pkg-config (build lib with qmake, install, and then use pkg-config from cmake) than one line add_subdirectory(qwt) in cmake.

You are right of course. Qwt can support both cmake and qmake as many other modern qt projects. If we need support older qt versions there is no reason to drop qmake. But cmake is pretty simplier to manage thirdparty dependecies and qwt (with cmake support) can be easier used in modern cmake qt projects. So qwt will be more friendly for users.

@rathmann are there any chances for cmake in the upstream?

Zint is available from conan. Issue can be closed :)

getopt

CMakeLists - a bit modernization

Simpily CMakeLists

CMakeLists simplify