Nbase fails to build on Solaris 9 due to missing stdint.h

[dmiller-nmap]

In file included from netutil.cc:131:
../nbase/nbase.h:227:20: stdint.h: No such file or directory

Looks like the alternative is <inttypes.h> or <sys/int_types.h>, though perhaps <sys/int_limits.h> is needed as well? Likely affects non-Solaris systems, too (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=448).