1. Download GSL source tree from below, you will get "gsl-master.zip" file
    https://github.com/BrianGladman/gsl

2. Unzip, go to directory "build.vc", and run "gsl.lib.sln"

3. As prerequisite, firstly build "gsldefs" and then "gslhdrs"

4. Finally build the whole solution, including "cblaslib" and "gsllib"

Works with Visual Studio 2019.
