Where is alloca(3)?

[Chin Fang]

This afternoon I was trying to build xmail posted in comp.sources.x.  Everything
went on fine until linking time.  Make complained that .alloca was a unresolved
external reference and then quit.  Initially I thought it wasn't a big deal.  
I used to program on SYSTEM V boxes and if this was the case, just add -lPW would
normally fix it.  NOT this time!

So, I man alloca first and a partial quote is given as follows:

--------------------------  BEGIN OF QUOTE --------------------------------
fang> man alloca
  malloc, free, realloc, calloc, mallopt, mallinfo, or alloca Subroutine


   Key Concepts



  Purpose

  Provides a memory allocator.

  Libraries

  Standard C Library (libc.a), Berkeley Compatibility Library
  (libbsd.a)

---------------------------  END OF QUOTE ----------------------------------

The trouble is that even I nm(1) these two, I still couldn't find .alloca. 
Neither libPW.a has it.  Certainly putting anyone of them in Makefile wouldn't
do me any good :-(  

Of course, I can steal the alloca.c from GNU emacs and then do some hacking, but
I am curious where is this alloca(3) in AIX?  

Any hints would be appreciated.  Thanks in advance for any help.  Please email
your response(s).

Regards,

Chin Fang
Mechanical Engineering Department
Stanford University
fangchin at leland.stanford.edu