The coreutils sources get built against the regex.h included with
coreutils, but linked against the regex implementation in libroot. Some
of the types used by coreutils' regex implementation differ from those
in libroot's on 64-bit platforms meaning they are incompatible. Fixed by
building coreutils' own regex implementation rather than linking to
libroot's (GCC 2 still uses libroot though, coreutils' implementation
doesn't build with GCC 2).