Split helper classification macros from mathcalls.h

The classification macros: finite, fpclassify, iseqsig, isinf, isnan,
issignaling, and signbit are defined by ISO C11 and declared in
mathcalls.h for each of the floating-point types: float, double, and
long double.

TS 18661-3 does not mention these macros for float128, however support
for them must be present when _Float128 is present.  This is true,
even when the feature test macro __STDC_WANT_IEC_60559_TYPES_EXT__ is
false.  Other function declarations in mathcalls.h, on the other hand,
depend on __STDC_WANT_IEC_60559_TYPES_EXT__.

This patch splits the helper functions (__finite, __fpclassify,
__iseqsig, __isinf, __isnan, __issignaling, and __signbit) from
mathcalls.h, so that these helper functions can be declared for
_Float128, even when __STDC_WANT_IEC_60559_TYPES_EXT__ is false.

Tested for powerpc64le, s390x, and x86_64.

	* include/bits/mathcalls-helper-functions.h: New file.
	* math/Makefile (headers): Add bits/mathcalls-helper-functions.h.
	* math/bits/mathcalls.h (__finite, __fpclassify, __iseqsig)
	(__isinf, __isnan, __issignaling, __signbit): Move declarations to
	math/bits/mathcalls-helper-functions.h.
	* math/bits/mathcalls-helper-functions.h: New file.
	* math/math.h: Include bits/mathcalls-helper-functions.h for
	float, double, and long double.

1 files changed, 43 insertions, 0 deletions

diff --git a/math/bits/mathcalls-helper-functions.h b/math/bits/mathcalls-helper-functions.h
new file mode 100644
index 0000000000..dec2d99f69
--- /dev/null
+++ b/math/bits/mathcalls-helper-functions.h
@@ -0,0 +1,43 @@
+/* Prototype declarations for math classification macros helpers.
+   Copyright (C) 2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+
+/* Classify given number.  */
+__MATHDECL_1 (int, __fpclassify,, (_Mdouble_ __value))
+     __attribute__ ((__const__));
+
+/* Test for negative number.  */
+__MATHDECL_1 (int, __signbit,, (_Mdouble_ __value))
+     __attribute__ ((__const__));
+
+/* Return 0 if VALUE is finite or NaN, +1 if it
+   is +Infinity, -1 if it is -Infinity.  */
+__MATHDECL_1 (int, __isinf,, (_Mdouble_ __value)) __attribute__ ((__const__));
+
+/* Return nonzero if VALUE is finite and not NaN.  Used by isfinite macro.  */
+__MATHDECL_1 (int, __finite,, (_Mdouble_ __value)) __attribute__ ((__const__));
+
+/* Return nonzero if VALUE is not a number.  */
+__MATHDECL_1 (int, __isnan,, (_Mdouble_ __value)) __attribute__ ((__const__));
+
+/* Test equality.  */
+__MATHDECL_1 (int, __iseqsig,, (_Mdouble_ __x, _Mdouble_ __y));
+
+/* Test for signaling NaN.  */
+__MATHDECL_1 (int, __issignaling,, (_Mdouble_ __value))
+     __attribute__ ((__const__));