Downloading Files
1) Download and install Virtual Machine. Any modern virtual machine capable of making snapshots will do, for example VMware Workstation. This tutorial assumes Oracle VirtualBox because it's available free of charge.
2) Download source code for gcc-4.9.2, binutils-2.25, glibc-2.19 and gdb-7.7.1 from ftp://ftp.gnu.org/. It's recommended to download full gcc package for this tutorial.
3) Download source code for Linux kernel (4.1.19 will do).
4) Download additional patches for glibc from this website. They are required for glibc to build under Cygwin.
5) GCC dependency libraries (libgmp, libmpfr, and libmpc) between 2012 and 2016 have become a part of MinGW and Cygwin, so it's no longer necessary to download and build them manually.
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