Make sure that the installation path does not have spaces in it, because Bison does not correctly quote paths when passing them to m4. Make sure you don’t download it from because we hardcode the executable name as “python2.7” and the python doesn’t include an executable with that name. Make sure it’s version 2.x instead of 3.x. Installing Development Toolsīegin by installing the following programs and setting up your environment: You can optionally install Cygwin in order to run tests. This guide provides instructions for building WebKit on Windows 8.1 without Cygwin (the AppleWin port of WebKit).