checking for emacs... no
checking for xemacs... no
checking where .elc files should go... ${datadir}/emacs/site-lisp
checking for ANSI C header files... (cached) yes
checking for unistd.h... (cached) yes
checking errno.h usability... yes
checking errno.h presence... yes
checking for errno.h... yes
checking for stdint types... stdint.h (shortcircuit)
make use of stdint.h in lib/idn-int.h (assuming C99 compatible system)
checking whether strerror_r is declared... yes
checking for strerror_r... yes
checking whether strerror_r returns char *... no
checking whether strdup is declared... yes
checking for error_at_line... yes
checking getopt.h usability... yes
checking getopt.h presence... yes
checking for getopt.h... yes
checking for getopt_long_only... yes
checking whether optreset is declared... no
checking for strdup... yes
checking if setlocale() and nl_langinfo() works... yes
checking if TLD API for specific TLD rules should be built... yes
checking for pkg-config... /usr/bin/pkg-config
checking if /opt/blackdown-jdk-1.4.2.03/bin/javac works... configure: error: The Java compiler /opt/blackdown-jdk-1.4.2.03/bin/javac failed (see config.log, check the CLASSPATH?)

!!! Please attach the following file when filing a report to bugs.gentoo.org:
!!! /var/tmp/portage/net-dns/libidn-0.5.15/work/libidn-0.5.15/config.log

!!! ERROR: net-dns/libidn-0.5.15 failed.
Call stack:
  ebuild.sh, line 1614:   Called dyn_compile
  ebuild.sh, line 971:   Called qa_call 'src_compile'
  environment, line 2090:   Called src_compile
  libidn-0.5.15.ebuild, line 30:   Called econf '--enable-nls' '--enable-java'
  ebuild.sh, line 577:   Called die

!!! econf failed
!!! If you need support, post the topmost build error, and the call stack if relevant.
!!! A complete build log is located at '/var/tmp/portage/net-dns/libidn-0.5.15/temp/build.log'