remove inappropriate dependencies on system headers
|Reported by:||andrewbachmann||Owned by:||bonefish|
Building haiku should be self-standing with respect to headers. Although building the build tools will naturally use the system headers, haiku itself should be able to build from the headers that are in the repository.
Some tests may reasonably run natively in which case they would use system headers, but tests that are intended to be run on haiku should not use system headers.