The configure-time detection (cxx11default) isn't enough if the compiler
can be changed. This is especially necessary if Qt is compiled with a
compiler that defaults to >= C++11 (e.g., GCC 6) and then the user
selects a compiler another compiler (e.g., Clang) via -spec option. In
that case, we'd miss adding the -std=c++11 or -std=gnu++11 option to the
command-line, causing the compilation to fail.
As a nice side-effect, even moc without moc_predefs.h will now get the
__cplusplus setting.
Task-number: QTBUG-58321
Change-Id: I74966ed02f674a7295f8fffd14a8be35da9640e1
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
this makes it consistent with the determination of the default
include/library paths. this makes sense, as it's possible to switch the
sdk/toolchain after building qt (within reason).
a side effect of this change is that for compilers which emulate other
compilers, both the real and the emulated version are now made
available.
Change-Id: Icfcc672c0d2e3d1b5e622993c366063d70ad327c
Started-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
