Version 6.4.1

Improvements and bug fixes:

• Fix progress showing a wrong job name.
• Show console output if CMake generation fails.
• Fix cmake flags source overwriting CMAKE_PREFIX_PATHS environment variable.
• Add more suffixes to find libclang, thanks @jeeb.
• Fix docs generation after updating the theme.

Development announcement:

I decided to move away from using the "dev" branch. Now all the development
will be happening in the "master" branch. The releases will be sourced from
the "release" branch. See contribution guidelines for details.