porting code based on linuxthreads to NPTL?

Motivation:

Mysqld has been unstable running on NPTL (I posted a note about this awhile 
back and filed a bug @mysqld.com).

I've replicated the problem on rh 9 and kernel 2.5.7[45] with nptl 0.51, 
where high loads result in a hung daemon.

The workaround suggested from mysql.com (for redhat) was:

export LD_ASSUME_KERNEL=2.2.5; mysqld_safe &

Which apparently selects the RH LinuxThreads support at runtime.

I'd like to get mysql running on NPTL to test performance, and 
this would seem to require source-changes at this point.


Attempting to build mysqld working against NPTL (0.57 / 2.6.0-test4)
is failing apparently due to different function prototypes.



Question:

Can anyone give me some pointers on what I'm going to need to change 
in to port a linuxthreads-based source to NPTL?


Of course pointers on how to fix this in autotools would be great too.
Ive tracked this down to:

choosing a threading library other than mysql's default:

./configure --with-named-thread-libs=-lpthread 

removes  #define HAVE_LINUXTHREADS which in turn fails to load function
prototypes and so far my attempts to fix that have show that nptl's
functions have more (/ different?) arguments than LinuxThreads.


elaine