* All files with FSF copyright notices: Update copyright dates
	using scripts/update-copyrights.
	* locale/programs/charmap-kw.h: Regenerated.
	* locale/programs/locfile-kw.h: Likewise.

As noted in bug 21607, NO_LONG_DOUBLE conditionals in libm tests are
no longer effective.  For most this is harmless - they were only
present because of long double functions not being declared with _LIBC
defined, and _LIBC is no longer defined for building most tests.  For
the few where this is actually relevant to the test, testing
LDBL_MANT_DIG > DBL_MANT_DIG is more appropriate as that limits the
test to public APIs.  This patch fixes the tests accordingly.

Tested for x86_64 and arm.

	[BZ #21607]
	* math/basic-test.c [!NO_LONG_DOUBLE]: Change conditionals to
	[LDBL_MANT_DIG > DBL_MANT_DIG].
	* math/bug-nextafter.c [!NO_LONG_DOUBLE]: Remove conditionals.
	* math/bug-nexttoward.c [!NO_LONG_DOUBLE]: Likewise.
	* math/test-math-isinff.cc [!NO_LONG_DOUBLE]: Likewise.
	* math/test-math-iszero.cc [!NO_LONG_DOUBLE]: Likewise.
	* math/test-nan-overflow.c [!NO_LONG_DOUBLE]: Likewise.
	* math/test-nan-payload.c [!NO_LONG_DOUBLE]: Likewise.
	* math/test-nearbyint-except-2.c [!NO_LONG_DOUBLE]: Likewise.
	* math/test-nearbyint-except.c [!NO_LONG_DOUBLE]: Likewise.
	* math/test-powl.c [!NO_LONG_DOUBLE]: Likewise.
	* math/test-signgam-finite-c99.c [!NO_LONG_DOUBLE]: Likewise.
	* math/test-signgam-finite.c [!NO_LONG_DOUBLE]: Likewise.
	* math/test-signgam-main.c [!NO_LONG_DOUBLE]: Likewise.
	* math/test-snan.c [!NO_LONG_DOUBLE]: Likewise.
	* math/test-tgmath-ret.c [!NO_LONG_DOUBLE]: Likewise.
	* math/test-tgmath.c: Include <float.h>.
	[!NO_LONG_DOUBLE]: Change conditionals to [LDBL_MANT_DIG >
	DBL_MANT_DIG].
	* math/test-tgmath2.c: Include <float.h>.
	[!NO_LONG_DOUBLE]: Change conditionals to [LDBL_MANT_DIG >
	DBL_MANT_DIG].

These have helped me find and fix type conversion issues in QEMU's MIPS
hardware emulation.  While certainly glibc is not the best place for such
tests, they're just an enhancement of tests already present.

It is based on draft TS 18661 and currently enabled as a GNU extension.