Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Oops, the weak reference for ceill(), floorl() and truncl() was in the
wrong file. This broke arm and powerpc.

Reported by: grehan

Forced commit to note that the lost log message for the previous commit
said that the previous commit was almost a null forced commit too. It
just converted to __FBSDID(). I was going to change `huge' from its
double precision value of 1e300, but that seems to be unnecessary since
`huge' is only used to set FE_INEXACT, and any value with an exponent
larger than LDBL_MANT_DIG will do for that, while initializing a really
huge value in a portable way would require more code.

s_ceill.c
s_floorl.c
s_truncl.c

On arches where long double is the same as double, alias ceil(), floor()
and trunc() to the corresponding long double functions. This is not
just an optimization for these arches. The full long double functions
have a wrong value for `huge', and the arches without full long doubles
depended on it being wrong.

Fix the C version of ceill(x) for -1 < x <= -0 in all rounding modes.
The result should be -0, but was +0.

Revert the last change, the conversion from long double to double can raise
unwanted underflow exceptions.

Pointed out by: das

Use double additions to raise the inexact exception to work around problems
with long double addition on sparc64.

Fix raising the inexact exception (FE_INEXACT) if the result differs from the
argument.

Noticed by: das

Implement and document ceill().