Add QFileDevice::MemoryMapFlags::MapPrivateOption flag.

Passing this flag to QFileDevice::map() will allow writes to the mapped memory
without modifying the file that was mapped. These writes will be lost when the
memory is unmapped.

Change-Id: I7d46b044fc370585de8c06fdb4059f1f1be12d7d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Make QRingBuffer::append() not leave empty arrays in buffer list

Change-Id: I4c5af33488a70996299289ec2b953b7bf3b2c428
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
rcc: String literal conversion cleanup

Replace QString::fromUtf8 with QString::fromLatin1 for ascii strings.
Also optimize use of QT_VERSION_STR.

Change-Id: I13c683499c56cb4ac4d2bbd9b6b53c337917e347
Reviewed-by: hjk <hjk121@nokiamail.com>
Introduce Q_DECL_UNUSED_MEMBER for clang

Since version 3.2, clang warns about unused member variables
(-Wunused-private-field). Marking such members with
Q_DECL_UNUSED_MEMBER will silence this warning.

This is a cleaner way than using Q_UNUSED() somewhere in the class
methods (like we did previously in qloggingcategory.cpp). It
mirrors Q_DECL_UNUSED for unused variables, which however can't be
used unconditionally for member variables because e.g. gcc will
complain.

Change-Id: I2afff683a7c3bae3bdcd684e5085a643887bb2a0
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: hjk <hjk121@nokiamail.com>