rebuilding the shared libc

[forsyth at minster.york.ac.uk]

has anyone worked out precisely what ld options, and import and
export files to use to build a new version of the C library,
with some functions replaced?
(we are running rs6000 aix version 3003.)

everything i have tried yields undefined symbols, redefinitions,
or an implausibly small shr.o (much smaller than the original)

perhaps someone else has already worked through all this (eg, the aix developers)
and could either post the details or tell me where to find them!