Fixed getDebugLevel handling of empty env var
Fixed getDebugLevel handling of empty env var

Reformulated strtoul() error checking to also check if the returned 'afterValue' is set to the beginning of the input sting, which indicates that there were no digits at all.

libexpat/libexpat,libexpat/libexpat,libexpat/libexpat,libexpat/libexpat,libexpat/libexpat,libexpat/libexpat