Activate Native Language Support (NLS) for error messages

Error messages have been in English regardless of the locale selected by
the user.  NLS support has always been possible, but it's never been
activated.  A simple CFLAG (-DNLS) does that now.  At the same time, NLS
support was added for network messages.
libm: Update erf, add imprecise versions of missing c++11 functions

Provide updates to erf and erff functions.

Also add weak versions of the missing c++11 long double functions by
using taking arguments of type double.  Use of these versions will
result in a linker warning to discourage program that really need
extra precision from using them.

Note that since the c/c++ specs only guarantee that long double has
precision equal to double, code that relies on these functions having
greater precision is unportable at best and broken at worst.

Taken-from: FreeBSD