I semi-recently switched to using egcs as my C/C++ compiler, so I now
have a libstdc++.so.1.0, along with the libstdc++.so.0.1 I had from the
old g++:

-r--r--r--  1 root  wheel  293735 Apr 10 16:57 /usr/lib/libstdc++.so.0.1
-r--r--r--  1 root  wheel  318231 May 27 07:01 /usr/lib/libstdc++.so.1.0

mozilla, which I compiled with the old g++ has quit working though... it
gives me:

/usr/libexec/ld.so: warning: libstdc++.so.1.0: minor version >= 1 expected, using it anyway
/usr/libexec/ld.so: Undefined symbol "___terminate" in mozilla-export:/usr/lib/libstdc++.so.1.0

ldd says:

/usr/X11R6/bin/mozilla-export:
/usr/libexec/ld.so: warning: libstdc++.so.1.0: minor version >= 1 expected, using it anyway
        -lXm.1 => /usr/X11R6/lib/libXm.so.1.2 (0x847e000)
        -lXt.6 => /usr/X11R6/lib/libXt.so.6.0 (0x8576000)
        -lXmu.6 => /usr/X11R6/lib/libXmu.so.6.0 (0x85b1000)
        -lXext.6 => /usr/X11R6/lib/libXext.so.6.3 (0x85c1000)
        -lX11.6 => /usr/X11R6/lib/libX11.so.6.1 (0x85cd000)
        -lSM.6 => /usr/X11R6/lib/libSM.so.6.0 (0x8655000)
        -lICE.6 => /usr/X11R6/lib/libICE.so.6.3 (0x865d000)
        -lc.12 => /usr/lib/libc.so.12.26 (0x866f000)
        -lg++.4 => /usr/lib/libg++.so.4.0 (0x86d7000)
        -lstdc++.0 => /usr/lib/libstdc++.so.1.0 (0x8709000)
        -lm.0 => /usr/lib/libm.so.0.1 (0x8749000)
        -lcurses.2 => /usr/lib/libcurses.so.2.2 (0x8761000)

So, if it was linked against stdc++.0, why's ld.so using stdc++.1? Sure,
it's got a higher version number, but I thought the idea was that
whenever the major version number changed, that meant the library wasn't
compatible with the previous version.

This is on mac68k from a few days ago (May 27, I'd guess), but I also
saw it with ftp on i386, when libedit's version changed and I hadn't
recompiled ftp yet.
-- 
Name: Dave Huang     |   Mammal, mammal / their names are called /
INet: khym@bga.com   |   they raise a paw / the bat, the cat /
FurryMUCK: Dahan     |   dolphin and dog / koala bear and hog -- TMBG
Dahan: Hani G Y+C 22 Y++ L+++ W- C++ T++ A+ E+ S++ V++ F- Q+++ P+ B+ PA+ PL++