Clang: Fix system pre include search path

We now get the resource path from creator. The -fPIC case is working now
too.

Change-Id: Id191e89e6d46706748d50440038a06a349972cc9
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

tests/unit/unittest/projectupdater-test.cpp

@@ -351,7 +351,6 @@ TEST_F(ProjectUpdater, ToolChainArguments)
 
     ASSERT_THAT(arguments,
                 ElementsAre(QString{"-m32"},
-                            QString{"-fPIC"},
                             QString{"extraflags"},
                             QString{"-include"},
                             QString{"config.h"}));