To support C/C++ 32 bit development libraries on CentOS-5.2 x86_64 arch the below devel packages are required:
yum install glibc-devel.i386 libstdc++-devel.i386Below is example output of multilib support for gcc:
$ gcc -print-multi-lib; gcc -print-multi-os-directory; gcc -print-multi-os-directory -m32
.;
32;@m32
../lib64
../lib