lib/48633: List of architectures supporting fenv.h is multiplied

[martin%NetBSD.org@localhost]

>Number:         48633
>Category:       lib
>Synopsis:       List of architectures supporting fenv.h is multiplied
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    lib-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Mar 03 16:00:00 +0000 2014
>Originator:     Martin Husemann
>Release:        NetBSD 6.99.33
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD unpluged.duskware.de 6.99.33 NetBSD 6.99.33 (UNPLUGED) #17: Sun 
Mar 2 23:01:50 CET 2014 
martin%night-owl.duskware.de@localhost:/usr/src/sys/arch/evbarm/compile/UNPLUGED
 evbarm
Architecture: earm
Machine: evbarm
>Description:
The list of architectures which support <fenv.h> is not centralized. Right
now there are at least three copies in the tree:
 - src/lib/libm/Makefile (spread in pieces, very ugly)
 - src/tests/lib/libm/Makefile
 - src/include/fenv.h

There should be a central place, like we have for other features 
(e.g. __HAVE_ATOMIC64_OPS) and it should not be duplicated.
>How-To-Repeat:
Code inspection
>Fix:
n/a