- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

These tests check whether the compiler evaluates floating-point
expressions properly. Some of the tests depend on the compiler
implementing C99's FENV_ACCESS pragma, and only commercial compilers
do; those tests are currently skipped. If any of the enabled tests
fail, then odds are the libm regression tests will fail also.
This should make it easier to diagnose reported problems on platforms
I don't have.

Currently, gcc passes all the tests that don't depend on FENV_ACCESS
on amd64 and sparc64. Clang fails a few on amd64 (see clang bug
11406). Both gcc and clang fare poorly on i386, which has well-known
issues.