[GTK] The list of features shown by cmake is not accurate
https://bugs.webkit.org/show_bug.cgi?id=134588

Reviewed by Gustavo Noronha Silva.

The problem is that some options might change after the feature
list has been printed.

* Source/cmake/OptionsGTK.cmake: Find package dependencies before
setting the default values of features and set WEBGL value
depending on the dependencies, and API_TEST depending on whether
developer mode is enabled or not.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@170751 268f45cc-cd09-0410-ab3c-d52691b4dbfc
[JavaScriptCore] Add --cmakeargs option to build-jsc.
https://bugs.webkit.org/show_bug.cgi?id=134590

Reviewed by Ryosuke Niwa.

* Scripts/build-jsc:


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@170752 268f45cc-cd09-0410-ab3c-d52691b4dbfc