From Dmitry Marakasov, "These are FreeBSD bits for src/osgPlugins/osc/osc/OscHostEndianness.h,
required to build newever OSG on this OS. Also corrects file name
in the error message - I was confused not to find OSCHostEndianness.h
after I've got this error.

Tested by successfully building OSG 3.2.0 with this patch on FreeBSD
9.1."