Actually, my /usr/lib/libc.so looks more like this:
/* GNU ld script
Use the shared library, but some functions are only in
the static library, so try that secondarily. */
*** BUG in libc/scripts/output-format.sed *** elf32-bigarm,elf32-littlearm
GROUP ( /lib/libc.so.6 /usr/lib/libc_nonshared.a )
I guess the BUG line can explain a lot of things, but I can't see how to work around this.