https://bugs.webkit.org/show_bug.cgi?id=113396

Reviewed by Philippe Normand.

So far, we were using the `MAKEFLAGS' environment variable to pass the
number of compilation jobs we wanted to jhbuild. jhbuild itself, on the
other hand, prefers to use the `jobs' variable from jhbuildrc for that.

We now behave more closely to the rest of the WebKit tools by first
checking the `NUMBER_OF_PROCESSORS' environment variable and, if it is
not set, just letting jhbuild itself figure out how many jobs to use.

* efl/jhbuildrc:
* gtk/jhbuildrc:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146979 268f45cc-cd09-0410-ab3c-d52691b4dbfc