Fix clang warning about bool to pointer conversion.

The operation is legal from C++ perspective but only for "false" as it
is guaranteed to be 0. Anyway returning 0 instead of "false" is
logical and it follows coding style used in the modified functions.

(cherry-picked from qt5 commit 50995e6936c5ca75a0a8a48c29bbbedd2cc60567)
Change-Id: Ia09758e8d28599097f5c40eb24722890508afdbc
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
Ukrainian translation update

Tiny fixes, mostly about copyright years.

Change-Id: I9223eaabccb1ce93f1688f3512344dbcfb05aa6a
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Check that 3DNow! instructions are supported before including mm3dnow.h.

Include mm3dnow.h the way we already include the (S)SSE{3,4} and AVX
instruction headers: by checking that the compiler is set to support those
instructions besides verifying that QT_HAVE_3DNOW evalues to true (which
only means the compiler supported them when the build was being configured).

This has not caused a problem in most cases so far because GCC protects its
mm3dnow.h header with an #ifdef __3dNOW__ (contrary to what it does on, say,
pmmintrin.h). clang's mm3dnow.h, on the other hand, does not have that check
and can fail if -march is set to, for example, i386 or i486.

Not backported from qt5 because qtbase because qsimd_p.h does not include
the 3DNow! headers after commit a1b30b49ef09bef2e97b9a0622bf7ad622678fee.

Change-Id: I15ab5e936c71c55f89c3f25777ab27fbd262e9cd
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>