conformtest: correct set of standards for which some headers are tested.

conformtest: correct set of standards for which some headers are tested.

Reviewing the sets of headers for which conformtest has expectations
for various standards showed up cases where headers had expectations
for standards not including those headers, or were missing
expectations for a standard that did include the header.  This patch
fixes easy cases of this (largely disabling tests for standards for
which they are inapplicable).  Tested x86_64.

	* conform/data/aio.h-data [XPG3 || XPG4]: Disable whole file.
	* conform/data/arpa/inet.h-data [XPG3]: Likewise.
	* conform/data/dlfcn.h-data [XPG3 || XPG4]: Likewise.
	* conform/data/fmtmsg.h-data [XPG3]: Likewise.
	* conform/data/libgen.h-data [XPG3]: Likewise.
	* conform/data/mqueue.h-data [XPG3 || XPG4]: Likewise.
	* conform/data/ndbm.h-data [XPG3]: Likewise.
	* conform/data/net/if.h-data [XPG3 || XPG4 || UNIX98]: Likewise.
	* conform/data/netdb.h-data [XPG3]: Likewise.
	* conform/data/netinet/in.h-data [XPG3]: Likewise.
	* conform/data/poll.h-data [XPG3]: Likewise.
	* conform/data/spawn.h-data [XPG3 || XPG4 || UNIX98]: Likewise.
	* conform/data/strings.h-data [XPG3]: Likewise.
	* conform/data/stropts.h-data [XPG3]: Likewise.
	* conform/data/sys/mman.h-data [XPG3]: Likewise.
	* conform/data/sys/resource.h-data [XPG3]: Likewise.
	* conform/data/sys/select.h-data [XPG3 || XPG4 || UNIX98]:
	Likewise.
	* conform/data/sys/statvfs.h-data [XPG3]: Likewise.
	* conform/data/sys/time.h-data [XPG3]: Likewise.
	* conform/data/sys/timeb.h-data [XPG3]: Likewise.
	* conform/data/sys/uio.h-data [XPG3]: Likewise.
	* conform/data/sys/un.h-data [XPG3]: Likewise.
	* conform/data/syslog.h-data [XPG3]: Likewise.
	* conform/data/ucontext.h-data [XPG3]: Likewise.
	* conform/data/utmpx.h-data [XPG3]: Likewise.
	* conform/data/varargs.h-data [UNIX98]: Enable file.