* Use locale-independent string->float conversion
strtof and friends are locale aware and won't parse decimal numbers
with a period ("12.6" for instance) in locales that use another
character for the decimal period ("," in French for instance).
This change introduces a new function called strtof_c that forces
the use of a specific locale (called "C") to make sure we always
parse floats in the desired "C" format ("12.6").
With C++17 we should be able to use std::from_chars but this API
is not implemented in clang for floats at the moment.
* Fix Linux
