configure and curl-config --libs problem

Hi!

I tried to compile darcs-1.0.0 on Fedora Core 3 and configure script 
failed with:
configure: error: Cannot find system's zlib library; please set the 
LDFLAGS environment variable!
After some debugging it turned out that the issue was not zlib (which 
was installed), but rather the command configure used for testing of 
zlib sanity which included -lidn:
 gcc -o conftest  -O2    -L/usr/lib -lcurl -L/usr/kerberos/lib -lssl 
-lcrypto -lgssapi_krb5 -lkrb5 -lcom_err -lk5crypto -lresolv -ldl -lz 
-lgssapi_krb5 -lkrb5 -lk5crypto -lcom_err -lresolv -L/usr/kerberos/lib 
-lidn -lssl -lcrypto -lssl -lcrypto -lgssapi_krb5 -lkrb5 -lcom_err 
-lk5crypto -lresolv -ldl -lz -lz conftest.c -lz
Since libidn was not installed on the machine it caused gcc to fail. 
When I installed it, then everything went fine.
Now that insane library list came from running curl-config --libs early 
during config and then stuffing it to LDFLAGS which was used for all 
subsequent testing.
Is it possible to change configure to use "curl-config --libs" only 
during testing of libcurl and print more sensible error message? Or this 
is a bug in autoconf and there is no workaround for it?
Regards, Igor