问题
Is it necessary to install Cygwin (which includes diff) or MinGW (which presumably also does) for something as simple as determining the differences between foobar.txt and foobar.txt~?
回答1:
You don't need those long as you have a diff.exe program, such as the GNUWin32 diff-utils version, in your PATH. Emacs itself doesn't include the mechanics for performing the diffs.
来源：https://stackoverflow.com/questions/11458450/can-i-run-emacs-m-x-ediff-on-windows-without-installing-cygwin