On Hurd, 'ldd' from glibc does not find the dependent libraries when their lookup requires rpath entries that use $ORIGIN. On Linux, in contrast, this works.

How to reproduce:
Take main.c and lib.c from the attachments.

On Hurd:
$ gcc -Wall -shared -o libfoo.so lib.c
$ mkdir inst1
$ gcc -Wall -o inst1/main main.c libfoo.so '-Wl,-rpath,$ORIGIN'
$ mv libfoo.so inst1/libfoo.so
$ inst1/main
bar -> 42
$ ldd inst1/main
        libfoo.so => not found
        libc.so.0.3 => /lib/i386-gnu/libc.so.0.3 (0x01012000)
        /lib/ld.so => /lib/ld.so.1 (0x08000000)
        libmachuser.so.1 => /lib/i386-gnu/libmachuser.so.1 (0x01258000)
        libhurduser.so.0.3 => /lib/i386-gnu/libhurduser.so.0.3 (0x01271000)
$ mv inst1 inst2
$ inst2/main
bar -> 42
$ ldd inst2/main
        libfoo.so => not found
        libc.so.0.3 => /lib/i386-gnu/libc.so.0.3 (0x01012000)
        /lib/ld.so => /lib/ld.so.1 (0x08000000)
        libmachuser.so.1 => /lib/i386-gnu/libmachuser.so.1 (0x01258000)
        libhurduser.so.0.3 => /lib/i386-gnu/libhurduser.so.0.3 (0x01271000)
$ ldd --version
ldd (Debian GLIBC 2.28-7) 2.28
...
$ readelf -d inst2/main
...
0x0000001d (RUNPATH)                          Library runpath: [$ORIGIN]
...

For comparison, on Linux (good results):
$ gcc -Wall -shared -o libfoo.so lib.c
$ mkdir inst1
$ gcc -Wall -o inst1/main main.c libfoo.so '-Wl,-rpath,$ORIGIN'
$ mv libfoo.so inst1/libfoo.so
$ inst1/main
bar -> 42
$ ldd inst1/main
        linux-vdso.so.1 =>  (0x00007ffc75f32000)
        libfoo.so => /devel/ldd-bug/inst1/libfoo.so (0x00007f8c5357c000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f8c531b2000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f8c5377e000)
$ mv inst1 inst2
$ inst2/main
bar -> 42
$ ldd inst2/main
        linux-vdso.so.1 =>  (0x00007fffcfb7d000)
        libfoo.so => /devel/ldd-bug/inst2/libfoo.so (0x00007f9ffbf2e000)
        libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f9ffbb64000)
        /lib64/ld-linux-x86-64.so.2 (0x00007f9ffc130000)