* add Windows platform support for package gnu-gsl
* remove usefulless comment
* Update gnu-gsl to latest 2.7.1
* lowercase sha256
* change all sha256 string to lowercase
* gnu-gsl only patch on windows
* Rename CMakeLists.txt to cmakelists.txt
* rename CMakeLists.txt to cmakelists.txt
* move patches and cmakelists to sub-folders
* Update xmake.lua
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Co-authored-by: star9029 <hengxings783@gmail.com>