Current ebuild for opencascade does report incorrect USEflags in src_compile() along with preparing configure arguments. This has the disadvantage that all those checks are performed after unpacking and preparing the sources, which takes a lot of time. I think that such checks, especially X<->opengl one, should be performed within pkg_setup() instead of src_compile(), so that with incorrect USEflags the emerge process would fail or could be aborted without wasting a lot of time on unpacking the package.
1) it's in the main tree now 2) I changed that code when I moved it :)
