I'm moving to a new Linux build box. My original Linux box is a 32-bit Fedora FC14. My new Linux box is a 64-bit Fedora FC14.
Our compiler toolchain is a 32-bit app. The compiler didn't run on the new box, giving a cryptic error about /ld/ld-linux.so.2
Dug around Google. There are two postfixes (?) on FC14 packages: .i686 and .x86_64 (FC13 used .i586).
Short story: as root,
rpm -i bzip2-libs.i686
The dependency pulled in the 32-bit glibc. Probably could have installed just glibc.i686
The two glibc versions are installable side-by-side.