how does libc5-compat work?

["Thomas Gebhardt" <gebhardt@HRZ.Uni-Marburg.DE>]

Hi,

obviously it is still possible to run (most) of the old libc5
binaries in hamm. Somehow ld knows when it is necessary to use
the libs from the libc5-compat directory. How does this
mechanism work?

I have a program that segfaults; obviously it tries to use both
libc5 *and* libc6:

$ ldd secude
        /lib/nfslock.so.0 => /lib/nfslock.so.0 (0x4000c000)
        libsecude.so => /tmp/sec518c-linux/libsecude.so (0x4000e000)
        libgdbm.so.1 => /usr/lib/libgdbm.so.1 (0x4016a000)
        libdl.so.1 => /lib/libdl.so.1 (0x40170000)
        libc.so.5 => /lib/libc.so.5 (0x40173000)
        libc.so.6 => /lib/libc.so.6 (0x40231000)
        ld-linux.so.2 => /lib/ld-linux.so.2 (0x402d6000)         

How can I manage to get it working?

Thanks, Thomas