[PATCH v2] msvcrt: Call cdecl functions with empty FPU stack in _CI* functions

[Piotr Caban]

The FPU stack should be empty on cdecl function call. Failing to do so
breaks GCC 6.4.0 -O2 optimized code.

For bug #43940.

Signed-off-by: Piotr Caban 
---
  dlls/msvcrt/math.c | 263 
++++++++++++++++++++++-------------------------------
  1 file changed, 108 insertions(+), 155 deletions(-)