* The rtti fix actually dug up a bug in the scons build scripts.
* Autotools took the LLVM cpp and cxx flags, while scons only took
the cpp flags.
* This grabs the cxx flags and applies them where needed. We may
want to make the same change for the llvm cpp flags in scons.
* The only linux platform I can find with LLVM no-rtti is Ubuntu.
* Fixes bug #70471
Tested-by: Vinson Lee <vlee@freedesktop.org>
Alexander von Gluck IV
94d05bf87a