extend gthr-posix.h with rwlock

[Luke Dalessandro]

David Edelsohn wrote:
>>>>>> Luke Dalessandro writes:
> 
> Luke> My problem is that unwind-dw2-fde.c seems to be compiled multiple times during 
> Luke> a gcc build, and sometimes my additions are found but other times they are 
> Luke> not. I am rebuilding again (AIX 5.1), and I'll post more information for 
> Luke> anyone that needs it.
> 
> Luke> In the meantime, is there a how-to anywhere that describes adding or modifying 
> Luke> gthr.h models in gcc?
> 
> 	AIX multilibs pthread support.  Unlike Linux, AIX does not provide
> weak versions of the pthread symbols when operating in single-threaded
> mode.  AIX uses gthr-aix.h, which includes gthr-posix.h or gthr-single.h
> depending on the -pthread option.

Thank you, this was indeed the problem. I added the needed stubbs in 
gthr-single.h and it now compiles fine. Unfortunately there seems to be 
something wrong with my installation of ld as linking fails with a large 
number of errors of the form:

ld: 0711-252 SEVERE ERROR: File auxiliary symbol entry 1 in object _negdi2_s.o:
         Field x_offset contains 4. Valid values are between 4 and -1.
         The object name is being substituted.

Unfortunately I have almost no experience with AIX. I'll look for a prebuilt 
ld that seems newer than mine to see if this helps the problem.

Thank you for your help.

Luke