conformtest: Correct some unistd.h expectations for XPG3, XPG4.

The conformtest tests of unistd.h fail for XPG3 because of various
expectations that are incorrect for XPG3.  This patch corrects those
bogus expectations, and one bogus expectation for XPG4.  (This is not
based on a full review of the standards so there may well still be
other bugs in the expectations for this header.)

Tested for x86_64 and x86.

	* conform/data/unistd.h-data (F_LOCK): Do not expect for [XPG3].
	(F_ULOCK): Likewise.
	(F_TEST): Likewise.
	(F_TLOCK): Likewise.
	(useconds_t): Likewise.
	(intptr_t): Do not expect for [XPG3] or [XPG4].
	(brk): Do not expect for [XPG3]
	(fchown): Likewise.
	(fchdir): Likewise.
	(ftruncate): Likewise.
	(getdtablesize): Likewise.
	(gethostid): Likewise.
	(getpagesize): Likewise.
	(getpgid): Likewise.
	(getsid): Likewise.
	(getwd): Likewise.
	(lchown): Likewise.
	(lockf): Likewise.
	(readlink): Likewise.
	(sbrk): Likewise.
	(setpgrp): Likewise.
	(setregid): Likewise.
	(setreuid): Likewise.
	(symlink): Likewise.
	(sync): Likewise.
	(truncate): Likewise.
	(ualarm): Likewise.
	(usleep): Likewise.
	(vfork): Likewise.
	* conform/Makefile (test-xfail-XPG3/unistd.h/conform): Remove
	variable.