[Development] qt-4.8.x gcc5 version/detection issues

[Rex Dieter]

Found a couple more gcc5-related issues with qt-4.8.x builds:

* webkit components don't build, this is due to a configure check for 
gcc-4.x, here's my quick-n-dirty fix (for g++ stanza only, others probably 
should get touched too):

http://pkgs.fedoraproject.org/cgit/qt.git/tree/qt-fix_detection_of_gcc5.patch


* QT_BUILD_KEY handling

Similar to webkit above, the configure bits about QT_BUILD_KEY only handles 
up to gcc-4.x.

For fedora 22, our gcc5 builds are done in a way that is (supposedly) ABI 
compatible to gcc4, so I'm currently using:
http://pkgs.fedoraproject.org/cgit/qt.git/tree/qt-gcc5_compat_qt_build_key.patch
to ensure QT_BUILD_KEY matches (ie, it includes the same g++-4 string as 
before).

As far as upstream is concerned, I assume you'd prefer the default here to 
be g++-5 ?


Both of these are fairly simple/obvious, is this sufficient or would you 
rather I post something to codereview?


-- Rex