DOC: Update references to Cygwin

The Cygwin compiler is no longer supported -- we now support Mingw-w64.

Author: thewtex

SoftwareGuide/Latex/Introduction/Installation.tex

@@ -15,7 +15,7 @@ \chapter{Configuring and Building ITK}
 
 ITK has been developed and tested across different combinations of operating
 systems, compilers, and hardware platforms including Microsoft Windows, Linux on
-various architectures, UNIX, macOS, and Cygwin. Dedicated community members and
+various architectures, UNIX, macOS, and Mingw-w64. Dedicated community members and
 Kitware are committed to providing long-term support of the most prevalent
 development environments (Visual Studio, macOS, and Linux) for building ITK:
 
@@ -226,7 +226,7 @@ \section{Using CMake for Configuring and Building ITK}
 testing, and code generation.
 
 CMake generates native Makefiles or workspaces to be used with the corresponding
-development environment of your choice. For example, on UNIX and Cygwin systems,
+development environment of your choice. For example, on UNIX and MinGW systems,
 CMake generates Makefiles; under Microsoft Windows CMake generates Visual Studio
 workspaces; CMake is also capable of generating appropriate build files for
 other development environments, e.g., Eclipse. The information used by CMake is