[COMMITTED] tile: define __NO_LONG_DOUBLE_MATH

[Joseph Myers]

On Tue, 24 Nov 2015, Chris Metcalf wrote:

> as well, so it seemed uncontroversial.  And I only chose 2.12 on the theory
> that they
> should have been exported then.  I don't really care what version I export

That's not how things work.  The version is always the version where the 
symbols were actually first exported, not where they "should" have been 
exported; you never add symbols to a past release version.  See exp2l in 
math/Versions or fallocate64 in sysdeps/unix/sysv/linux/<various 32-bit 
architectures>/Versions for examples.

> them as, since there's really no way for userspace to generate a 
> reference to them,

Which is why it would be optimal not to export them at all.

> what would be cleaner here and I am happy to make the change, but it does seem
> like it should be a change for every platform without long double, not just
> tile.

Well, you don't remove symbols from old versions either.  Optimally the 
default should be that they aren't exported, with existing no-long-double 
platforms that had the exports defining some macro in their sysdeps files 
(e.g. math_private.h) to cause them to be exported (and ideally causing 
them to be exported as compat symbols only, given that it's not possible 
for the headers to generate references to them).

-- 
Joseph S. Myers
joseph@codesourcery.com