Fix compilation of ANGLE with mingw-tdm64 gcc 4.8.1

Do not rely on sprintf_s being declared/defined. This also fixes
deployment to Windows XP.

See https://chromium-review.googlesource.com/#/c/182975/ for a similar
commit proposed upstream.

Task-number: QTBUG-36242
Change-Id: I520e2f61aeab34963e7a57baafd413c7db93f110
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Work around FBO readback bug on Samsung Galaxy Tab 3

Symptom of the error is garbled text in Qt Quick 2, and the
fix has been confirmed to be enabling the texture resize workaround.

Task-number: QTBUG-34984
Change-Id: If6f621b43120c7913cbd33ab326c52ad6e2599bc
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>
Fix a bug in some QString comparison operators

Some comparison operators comparing to const char *
where not implemented correctly.

Task-number: QTBUG-34024
Change-Id: Idbdc64c8ed93e88d9f2b2f55213bc785b33cb543
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>