PG Extensions: Must be statically linked?

I'm creating user-defined server extensions, written in C per the manual "31.9. C-Language Functions". Everything works well, but only if I fully link the .so such that there are *no* unresolved external references at all. Not even the stuff in libstdc++.a can be left out. I've tried setting LD_LIBRARY_PATH everywhere possible, with no luck. Here's the make(1) line I have to use to link:

libmyfuncs.so.0.0:
gcc -Wall -Wmissing-prototypes -Wpointer-arith \
-Wdeclaration-after-statement -Wold-style-definition -Wendif-labels \
-fno-strict-aliasing -fpic -shared -Wl,-soname,libmyfuncs.so.0 \
$(OBJS) \
$(MYLIB)/lib/libmylibs.a \
/usr/lib/gcc/i386-redhat-linux/3.4.2/libstdc++.a \
-o libmyfuncs.so.0.0

Is this correct? Do Postgres extension need to be fully statically linked? Or is there some configuration that will specify LD_LIBRARY_PATH (or perhaps a Postgres-specific equivalent).

The manual's instructions are good regarding writing code, but don't say much about linking.

Thanks,
Craig