Only this old version of Cygwin can compile and run `ecos-tool/bin/configtool.exe` from `https://github.com/flyskywhy/ecos.git -b microblaze`. Plus, that configtool.exe can work with not only cygwin version gcc toochain but also native one to compile eCos application (ARM, MIPS, etc.). Green installed to `D:\cygwin\`. (<400MB)