Unresolved symbols when program imports std.regex

[GrahamC]

If I import std.regex in a program, compiling with gdc gives many unresolved symbols, e.g for:
  immutable(std.internal.uni.CodepointSet) std.internal.uni_tab.unicodeLu
  ref @safe std.internal.uni.CodepointSet std.internal.uni.CodepointSet.add(const(std.internal.uni.CodepointSet))
plus many others.

If I include additional modules on the compilation command line like this:

gdc test.d /opt/gdc/include/d2/4.6.2/std/internal/uni.d /opt/gdc/include/d2/4.6.2/std/internal/uni_tab.d

where test.d is my program, all symbols resolve OK.

Does this indicate a problem in the building of libgphobos2.a or have I made a mistake in configuring gdc
prior to compiling it ? I don't see any open issues listed for regex on https://bitbucket.org/goshawk/gdc/issues

gdc -v gives:
Using built-in specs.
COLLECT_GCC=gdc
COLLECT_LTO_WRAPPER=/opt/gdc/libexec/gcc/x86_64-unknown-linux-gnu/4.6.2/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../configure --enable-languages=d --enable-checking=release --disable-shared --disable-nls --prefix=/opt/gdc --with-bugurl=https://bitbucket.org/goshawk/gdc/issues --disable-libgomp --disable-libmudflap --enable-multilib --enable-nls
Thread model: posix
gcc version 4.6.2 20111026 (gdc 0.30, using dmd 2.057) (GCC)

My platform is Linux 3.1.5-6.fc16.x86_64