glibc 2.3 not binary compatible with glibc-2.2.5

[Christoph Lameter]

> miscompiled.  You'll have to provide more information since I for sure
> cannot reproduce any such problem.

Here is the end of the output of LD_DEBUG=all (run by overriding all the
paths to point to a local subdir so that it does not wreck my system
again):

00785:  binding file /home/christoph/t/lib/libpthread.so.0 to
/home/christoph/t/lib/libc.so.6: normal symbol `sigemptyset' [GLIBC_2.0]
00785:  symbol=memset;  lookup in file=/bin/tar
00785:  symbol=memset;  lookup in file=/home/christoph/t/lib/librt.so.1
00785:  symbol=memset;  lookup in file=/home/christoph/t/lib/libc.so.6
00785:  binding file /home/christoph/t/lib/libc.so.6 to
/home/christoph/t/lib/libc.so.6: normal symbol `memset' [GLIBC_2.0]
00785:  symbol=__libc_sigaction;  lookup in file=/bin/tar
00785:  symbol=__libc_sigaction;  lookup in
file=/home/christoph/t/lib/librt.so.1
00785:  symbol=__libc_sigaction;  lookup in
file=/home/christoph/t/lib/libc.so.6
00785:  binding file /home/christoph/t/lib/libpthread.so.0 to
/home/christoph/t/lib/libc.so.6: normal symbol `__libc_sigaction'
[GLIBC_PRIVATE]
00785:  symbol=__errno_location;  lookup in file=/bin/tar
00785:  symbol=__errno_location;  lookup in
file=/home/christoph/t/lib/librt.so.1
00785:  symbol=__errno_location;  lookup in
file=/home/christoph/t/lib/libc.so.6
00785:  symbol=__errno_location;  lookup in
file=/home/christoph/t/lib/libpthread.so.0
00785:  binding file /home/christoph/t/lib/libc.so.6 to
/home/christoph/t/lib/libpthread.so.0: normal symbol `__errno_location'
[GLIBC_2.0]
Segmentation fault

just with LD_DEBUG=libs:

k2-400:/home/christoph/t# lib/ld-linux.so.2 /bin/tar
00795:  find library=librt.so.1; searching
00795:   search
path=/home/christoph/t/lib/i586/mmx:/home/christoph/t/lib/i586:/home/christoph/t/lib/mmx:/home/christoph/t/lib:/home/christoph/t/usr/lib/i586/mmx:/home/christoph/t/usr/lib/i586:/home/christoph/t/usr/lib/mmx:/home/christoph/t/usr/lib
(LD_LIBRARY_PATH)
00795:    trying file=/home/christoph/t/lib/i586/mmx/librt.so.1
00795:    trying file=/home/christoph/t/lib/i586/librt.so.1
00795:    trying file=/home/christoph/t/lib/mmx/librt.so.1
00795:    trying file=/home/christoph/t/lib/librt.so.1
00795:
00795:  find library=libc.so.6; searching
00795:   search
path=/home/christoph/t/lib:/home/christoph/t/usr/lib/i586/mmx:/home/christoph/t/usr/lib/i586:/home/christoph/t/usr/lib/mmx:/home/christoph/t/usr/lib
(LD_LIBRARY_PATH)
00795:    trying file=/home/christoph/t/lib/libc.so.6
00795:
00795:  find library=libpthread.so.0; searching
00795:   search
path=/home/christoph/t/lib:/home/christoph/t/usr/lib/i586/mmx:/home/christoph/t/usr/lib/i586:/home/christoph/t/usr/lib/mmx:/home/christoph/t/usr/lib
(LD_LIBRARY_PATH)
00795:    trying file=/home/christoph/t/lib/libpthread.so.0
00795:
00795:
00795:  calling init: /home/christoph/t/lib/libpthread.so.0
00795:
Segmentation fault

How can I convince gdb to use another /lib/ld-linux.so.2 for loading?