Emerging net-fs/nfs-utils-1.2.4 with USE="ipv6 nfsv3 nfsv4 tcpd -caps -kerberos" fails complaining about lack of keyutils.h. Emerging sys-apps/keyutils fixes the issue. Therefore, nfs-utils should depend on keyutils. I haven't tried with other USE flags so can't tell whether it depends on their configuration or not. My system is ~amd64 with gcc 4.5.3.
Created attachment 285343 [details] Build log of nfs-utils without keyutils.
confirm this bug. problem code from configure.ac[1] 258 259 dnl check for the keyutils libraries and headers 260 AC_KEYUTILS 261 [1] http://git.linux-nfs.org/?p=steved/nfs-utils.git;a=blob;f=configure.ac;h=c9fb27b7bc0734330e7879809c11aa7d6856b3cf;hb=HEAD
*** This bug has been marked as a duplicate of bug 381459 ***