* Name the private function __strto_{int,fp} (with leading double
underscores) to avoid name conflicts
* Fix comments of the wrong style
* Fix missing leading double underscores in stdlib_p.h
The method is rather naive - digits read as an integer, then multipled
by a power of 10 or 2. This does not always give exact results, but it's
close enough for now. A stub support for long double larger than 64 bits
is provided.