Move SNAN_TESTS_TYPE_CAST out of math-tests.h.

The math-tests.h header has many different macros and groups of
macros, defined using #ifndef in the generic version which is included
by architecture versions with #include_next after possibly defining
non-default versions of some of those macros.

This use of #ifndef is contrary to our normal typo-proof conventions
for macro definitions.  This patch moves one of the macros,
SNAN_TESTS_TYPE_CAST, out to its own sysdeps header, to follow those
typo-proof conventions more closely.

Tested with build-many-glibcs.py.

2018-08-01  Joseph Myers  <joseph@codesourcery.com>

	* sysdeps/generic/math-tests-snan-cast.h: New file.
	* sysdeps/powerpc/math-tests-snan-cast.h: Likewise.
	* sysdeps/generic/math-tests.h: Include <math-tests-snan-cast.h>.
	(SNAN_TESTS_TYPE_CAST): Do not define macro here.
	* sysdeps/powerpc/math-tests.h (SNAN_TESTS_TYPE_CAST): Likewise.

2 files changed, 30 insertions, 8 deletions

diff --git a/sysdeps/powerpc/math-tests-snan-cast.h b/sysdeps/powerpc/math-tests-snan-cast.h
new file mode 100644
index 0000000000..13e941d0f6
--- /dev/null
+++ b/sysdeps/powerpc/math-tests-snan-cast.h
@@ -0,0 +1,30 @@
+/* Configuration for math tests: casts of sNaN values.  PowerPC version.
+   Copyright (C) 2013-2018 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/>.  */
+
+#ifndef POWERPC_MATH_TESTS_SNAN_CAST_H
+#define POWERPC_MATH_TESTS_SNAN_CAST_H 1
+
+/* On PowerPC, in versions of GCC up to at least 4.7.2, a type cast --
+   which is a IEEE 754-2008 general-computational convertFormat
+   operation (IEEE 754-2008, 5.4.2) -- does not turn a sNaN into a
+   qNaN (whilst raising an INVALID exception), which is contrary to
+   IEEE 754-2008 5.1 and 7.2.  This renders certain tests infeasible
+   in this scenario.  <https://gcc.gnu.org/PR56828>.  */
+#define SNAN_TESTS_TYPE_CAST	0
+
+#endif /* math-tests-snan-cast.h.  */
diff --git a/sysdeps/powerpc/math-tests.h b/sysdeps/powerpc/math-tests.h
index cf8adccefd..f95428a2d1 100644
--- a/sysdeps/powerpc/math-tests.h
+++ b/sysdeps/powerpc/math-tests.h
@@ -16,14 +16,6 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-/* On PowerPC, in versions of GCC up to at least 4.7.2, a type cast -- which is
-   a IEEE 754-2008 general-computational convertFormat operation (IEEE
-   754-2008, 5.4.2) -- does not turn a sNaN into a qNaN (whilst raising an
-   INVALID exception), which is contrary to IEEE 754-2008 5.1 and 7.2.  This
-   renders certain tests infeasible in this scenario.
-   <http://gcc.gnu.org/PR56828>.  */
-#define SNAN_TESTS_TYPE_CAST	0
-
 #ifndef __NO_FPRS__
 /* Setting exception flags in FPSCR results in enabled traps for those
    exceptions being taken.  */