r246237 - in /branches/ARM/sve-branch/libstdc++...

rsandifo@gcc.gnu.org rsandifo@gcc.gnu.org
Fri Mar 17 17:28:00 GMT 2017

Author: rsandifo
Date: Fri Mar 17 17:27:58 2017
New Revision: 246237

URL: https://gcc.gnu.org/viewcvs?rev=246237&root=gcc&view=rev
[libstdc++-v3] Fix detection of obsolete isnan

libstdc++-v3 configure checks whether old glibc inline definitions
of isnan would conflict with the libstdc++-v3 definitions and
works around them if so.  But if g++ 6.x build A is used to build
another g++ 6.x B, the configure step for B will pick up the math.h
installed alongside A instead of the glibc version.  configure will
then assume that the workaround isn't necessary, leaving B with a
broken cmath.

isinf already worked around this.  This patch extends the same fix
to isnan.  (Thanks to George for the fix.)

2017-03-10  George Lander  <george.lander@arm.com>

	* acinclude.m4 (glibcxx_cv_obsolete_isnan): Define
	_GLIBCXX_INCLUDE_NEXT_C_HEADERS before including math.h.
	* configure: Regenerate.


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