[PATCH 1/3] msvcrt: Rework strtod_helper to be reusable.

[Erich E. Hoover]

We have the same code for parsing doubles in several places, this
rework allows us to use the most complete version (strtod) for wcstod
(patch 2) and scanf floats (patch 3).  Many thanks go to Piotr for his
help with this.

Best,
Erich

[Piotr Caban]

Signed-off-by: Piotr Caban <piotr(a)codeweavers.com>