gcc builtin functions, e.g. memcpy, and namespace std

[Martin v. Loewis]

>   Dont forget it needs to work with overloading.  We have sqrt ([float | double
> | long double]), abs ([int | long | float | double | long double]), etc.

Overloading does not work for extern "C" function. At most one of
those can be extern "C".

Regards,
Martin