Fix warnings like
qalgorithms.h:40:16: warning: expected [error|warning|ignored] after `#pragma GCC diagnostic`
As the comment below also indicates, #pragma GCC diagnostic [push|pop]
is only supported from gcc 4.6 upwards. See also the GCC 4.6
changelog: https://gcc.gnu.org/gcc-4.6/changes.html
[ChangeLog][Compiler specific Changes] GCC: Fixed a regression introduced Qt 5.5.0
that generated lots of compiler warnings in Qt public headers when using
the (deprecated) version 4.5 of GCC.
Change-Id: I425388b61cd5fbf464a0f7dd46ce403d35c532a4
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
561ccd7ca3