Remove unused function "quadraticRoots"

qbezier.cpp(122): warning #177: function "quadraticRoots" was declared but never referenced

Change-Id: I590f59ed6e41462d0a14a9239adb8bd0acbeeae4
Reviewed-by: Gunnar Sletta <gunnar.sletta@digia.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
GitIgnore updates

* ANGLE artifacts
* qfeatures

Change-Id: I3cb8f78bf02119233f115ec53d536c05dd9776e7
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Cascade detection of SSE3 support and up

If SSE2 isn't supported, then SSE3 can't be either. Onwards and upwards
for SSSE3, SSE4.1, SSE4.2 and AVX. The test for AVX2 was already there.

Task-number: QTBUG-24773
Change-Id: I005258db52d8abcd407a99b8ebcc23cdea8e3d9f
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Remove unused -sse (CFG_SSE) option

This is a left-over from the cleanup of MMX/3dNow!/SSE support, which we
no longer have in Qt.

Change-Id: I48388710a499bddb518ae3c2b8a4ad989482f58c
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>