gcc error

I got this gcc error when trying to compile a package called libcfg
+-0.6.2. Does anyone know what it means?

configure:546: checking for gcc
configure:659: checking whether the C compiler (gcc -O2 -Wall -Wno-
shadow -pedantic ) works
configure:675: gcc -o conftest -O2 -Wall -Wno-shadow -pedantic
conftest.c 1>&5
configure:672: warning: return type defaults to 'int'
/Xcode2.5/usr/bin/../libexec/gcc/i686-apple-darwin8/4.0.1/ld: /usr/lib/
system/libmathCommon.A.dylib load command 6 unknown cmd field
collect2: ld returned 1 exit status
configure: failed program was:

#line 670 "configure"
#include "confdefs.h"