Add QSysInfo::cpuArchitecture() and fullCpuArchitecture()

This uses the same logic as the config.test, so we will return the same
string as the $$QT_ARCH variable in qmake for cpuArchitecture().

fullCpuArchitecture() is meant to be used in upgrade mechanisms, when
combined with the OS type.

Change-Id: If0dfee9eff75a07fa4c0778d204e0e768bf43074
Reviewed-by: Kai Koehne <kai.koehne@digia.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Add QSysInfo::osType()

This function returns the OS kernel type. It's usually the same as the
first part of the mkspec, in qmake, or the result of uname. Usually,
because it's not the case for a few systems, like Android, OS X, iOS,
BlackBerry, etc.

Change-Id: I295d92048d33ef02987e8696772ea89e925428d3
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Sergio Ahumada <sahumada@blackberry.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Add QSysInfo::osVersion() and prettyOsName()

Change-Id: I85ae6c434ba3125802fc94e3a4ec7d01b07eac35
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Add QSysInfo::osKernelVersion()

Change-Id: If9a41d8b9530d36b2b574fdb93111ed556e8bdf2
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Implement QSysInfo::osVersion() for BlackBerry

Change-Id: I4bab6f475ba812bb92f9a185528c54f28392355c
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>
Reviewed-by: Sergio Ahumada <sahumada@blackberry.com>
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Don't open /etc/os-release outside Linux and Debian GNU/kFreeBSD

It's not likely to exist outside them, so let's save on the code size.

Change-Id: I72f139ccd1367f218b33cb926dae58696a83a82e
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>