Replace conformtest.pl with conformtest.py.

Replace conformtest.pl with conformtest.py.

Continuing the consolidation on Python for various miscellaneous build
and test scripts, this patch moves conformtest from Perl to Python.

The substance of the tests run is intended to be the same as before,
except that the previous test for tags did not actually achieve the
intended purpose of verifying whether a tag was already declared, so
is changed to one that would actually fail for a tag that wasn't
declared, and a typo in the old test for variables being available
($xyzzy instead of xyzzy) would have made that test not use the
correct type (but it would have passed anyway with warnings).  No
attempt is made to keep the details of what the test output looks
like; instead, tests are given names which are made to follow PASS: /
FAIL: / XFAIL: / SKIP: / MISSING: as appropriate.

In the new version, there is more consistent parsing of test lines
(into a series of words, either surrounded by {} or separated by
spaces) that applies for all kinds of test lines, rather than the old
approach of different regular expressions for every kind of test.  A
few of the conform/data/ files are adjusted so their syntax works with
the new script (which now requires spaces in certain cases where the
old script tolerated them being missing, and does not allow stray
semicolons at the end of "function" lines).  Similarly, common logic
is used around what happens with a second subtest if a first one fails
(e.g., a test for a symbol's type if the test for availability fails),
rather than such logic being replicated separately for each kind of
test.  Common parsing also applies for test lines both when they are
lines for the header under test and when they are lines for another
header specified with allow-header, again unlike the old script.

Tested for x86_64, and with build-many-glibcs.py.

	* conform/conformtest.py: New file.
	* conform/conformtest.pl: Remove.
	* conform/GlibcConform.pm: Likewise.
	* conform/glibcconform.py (KEYWORDS_C90): New constant.
	(KEYWORDS_C99): Likewise.
	(KEYWORDS): Likewise.
	* conform/Makefile ($(conformtest-header-tests)): Use
	conformtest.py instead of conformtest.pl.  Do not pass --tmpdir
	option.  Use --header instead of --headers.
	* conform/data/arpa/inet.h-data: Remove trailing semicolons on
	function entries.
	* conform/data/spawn.h-data: Likewise.
	* conform/data/fcntl.h-data (openat): Add space after function
	name.
	* conform/data/wchar.h-data (wcscasecmp): Likewise.
	(wcscasecmp_l): Likewise.
	* conform/data/termios.h-data (c_cc): Add space after element
	name.