mkspecs: add qfeatures.pri to installed files

... so it will be found when included. That file was added with
commit 3b6b615334713cbfeb43409ff104244b55f4ce1f,
"export QT_NO_<foo> equivalents to the build system"

Change-Id: I38208aafe5b274d5976cec5d5149a41e6a963798
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
XCB: do not assume that sizeof(long)==4

The code was using the "long" type when a 32 bit type was actually
needed. This can cause bugs in those systems where "long" is 64 bits
wide, such as Linux x86-64 (which is LP64).

Task-number: QTBUG-34861
Change-Id: Iab289b2af3847dd62d8b4ecea51896936ca4c7a2
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Reviewed-by: Jørgen Lind <jorgen.lind@digia.com>