In some build environments, bits of WebKit are built separately. This means that some items (like the Tools/Scripts) directory are not always present.
The "build-generated-files.sh" script used on Windows assumes the Tools directory always exists, and expects a valid return value from `num-cpus`.
When this script is not present, it passes the result of this failed call to the "make -j" invocation, resulting in a runaway set of forks (a "fork bomb").
This patch corrects this problem by hard-coding a reasonable number of processes to use when the 'num-cpus' call cannot be executed.
Created attachment 233021 [details]
Committed r169927: <http://trac.webkit.org/changeset/169927>