This commit adds an option to build using CMake by adding
CMakeLists.txt. CMake builds are consistent with the builds currently
produced.

For Linux build, CPack produces artifacts consistent with the current
RPM specification.

CMake is also added to the CI pipeline in main.yml.

* Use "nullptr" instead of "NULL"

* Cosmetic fix

* bind2nd() and ptr_fun<>() is removed since C++17

bind2nd() and ptr_fun<>() are deprecated in C++11, and removed in C++17.
These functions are not available in LLVM's "libc++".
Use C++11 lambda expressions for them.

* Break long lines

* Add missing header for std::iswspace()

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