[PATCH 1/4 v3] msvcrt: Import _logb implementation from musl.

[Piotr Caban]

Signed-off-by: Piotr Caban <piotr(a)codeweavers.com>
---
v3:
  - fixed __ilogb and __ilogbf prototype

I was not able to reproduce the warnings while compiling with clang 
locally so I'm not sure if it's fixed (there's still int->float 
conversion when __ilogb is called inside _logb).

  dlls/msvcrt/math.c    | 47 +++++++++++++++++++++++++------------------
  dlls/msvcrt/unixlib.c |  9 ---------
  dlls/msvcrt/unixlib.h |  1 -
  3 files changed, 27 insertions(+), 30 deletions(-)