[lmi] [PATCH] Better support for non-x87 platforms

[Vadim Zeitlin]

 Hello,

 As promised, here are the changes which allow to set rounding mode when
not using x87 and so make the "round" and "round_to" tests pass in 64 bit
builds: https://github.com/vadz/lmi/pull/49

 I left a few comments there concerning some perhaps slightly less obvious
points, but globally the changes are pretty straightforward: we keep using
the same code as now, with as few changes as possible, when using x87 and
use the standard C++11 functions otherwise. I've checked that all tests now
pass under Linux in x86-64 build and that they still pass in the standard
32 bit MinGW build. I also tested the interactive floating point
environment test in the GUI in the latter (it wouldn't do anything, and so
doesn't even exist, in the former).

 Please let me know if you have any questions concerning any of this and I
really hope this patch can be applied and thus end 10+ years of my effort
to make this part of lmi work correctly in 64 bit builds.

 Thanks in advance!
VZ