Fix iOS simulator build after 1f0823c (Rewrite simd.prf to share more code)

Now that we rely on simd.prf for all SIMD sources (including NEON and SSE2),
we need to ensure that CONFIG has the right SIMD values to match simulator.

This worked before due to us checking QT_CPU_FEATURES.$$QT_ARCH and adding
directly to SOURCES.

Change-Id: I4ea7f559e83860eabff1948ad5d140bbb65454df
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Xcode: Don't show QMAKE_INTERNAL_INCLUDED_FILES from Qt (prf/pri)

We build "Supporting Files" out of QMAKE_INTERNAL_INCLUDED_FILES, which
is really not supposed to be exposed to the user like that, but since
the variable will hold user-included pri files eg., the Xcode generator
piggy-backs on this variable to list the files.

To make the project view in Xcode a bit cleaner we explicitly exclude
any file living inside the Qt directory, meaning we won't show all the
pri and prf files from Qt's mkspecs directory anymore.

Change-Id: I828700aceac5fdf3ea2b27d9ba3885543c2ad137
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@digia.com>