Ht:dig configuration fails with gentoo 1.3a with the following error: checking for ostream.h... no checking for iostream.h... no checking for fstream.h... no configure: error: To compile ht://Dig, you will need a C++ library. Try installing libstdc++. there is nothing useful in config.log =(
Apparently already reported here http://www.gentoo.org/~mkennedy/gcc31.html sorry =)