libpq block allocated before my malloc handler inits?

I am trying to build a small program with libpq as the interface to a
Postgre database. I am using the most current version. My program uses
malloc and free hooks to manage memory without having to request memory
from the system all the time. I expected that the init function
(__malloc_initialize_hook) would run before anything else, but after
opening a number of connections to the database with PQconnectdb, my
program blows up because of a free which refers to a block of memory
that wasn't allocated using my malloc function. My program runs without
a hitch if I comment out the PQconnectdb function calls.

Is there something that runs before my malloc init function in libpq?
If there is, is there a way to make it happen afterwards? Is there a
library interface which doesn't have hidden init functions?

Please reply to me directly as well as CCing to the list; I haven't
subscribed to the list.

Thank you very much for your input,

Rob Stoddard