msvcrt: Don't depend on the system's implementation of acos () & asin().

[Henri Verbeet]

2008/8/29 Dan Kegel <dank at kegel.com>:
> Henri wrote:
>> glibc implements acos() as the FPU equivalent of atan2(sqrt(1 - x ^ 2), x).
>
> I just looked, and there are several implementations of acos
> in glibc, and they all seem to very carefully choose
> how to do it based on how close x is to 1.
>
The specific implementation I was talking about is
http://sources.redhat.com/git/?p=glibc.git;a=blob;f=sysdeps/i386/fpu/e_acos.S;hb=HEAD
it's NetBSD derived, and it seems at least NetBSD and OpenBSD use the
same or a similar implementation. I couldn't quickly find what FreeBSD
uses, but I wouldn't be surprised if it uses something like that as
well.

>> This should be fixed on the glibc side as well
>
> Indeed.  Have you filed a bug report against glibc yet?
> I didn't see one at http://sourceware.org/bugzilla/
> Please be sure to attach a simple C program that
> reproduces the problem, or better yet, a patch
> to add a test case to their test suite.
>
I tried to create an account on their  bugzilla yesterday, but for
some reason I never got the confirmation mail. I'll probably try again
in a few days. http://sources.redhat.com/bugzilla/show_bug.cgi?id=2540
looks like a similar issue.