Do not define __BSD_VISIBLE/_XOPEN_SOURCE/_POSIX_C_SOURCE in
include/python2.7/pyconfig.h
This fixes x11-toolkits/py-wxPython30 build on head

PR:		192365
Exp-run:	self
Reviewed by:	jilles
With hat:	portmgr


git-svn-id: svn+ssh://svn.freebsd.org/ports/head@368066 35697150-7ecd-e111-bb59-0022644237b5