Emacs 21.3 / AIX 5.2 configure modification needed

[Dan Foster]

I was building Emacs 21.3 on an AIX 5.2 host using the IBM C compiler
(VisualAge C/C++ 6.0 + patches).

My problem is that configure selects the wrong settings:

Configured for `powerpc-ibm-aix5.2.0.0'.

  What operating system and machine description files should Emacs use?
        `s/aix3-2.h' and `m/ibmrs6000.h'

...it picks the AIX 3.2.x stuff which causes it to try and build some
stuff (HFT) that has not existed in 10 years. :) Hence, my subsequent
'make' eventually fails.

Looking at configure, I see this is because it only goes up to AIX 5.1
for automatic detection; it defaults to s/aix3-2.h / AIX 3.2.5 settings
if it does not match anything.

The fix is to add these three lines after the rs6000-ibm-aix-5.1* stanza:

  rs6000-ibm-aix5.2* | powerpc-ibm-aix5.2*  )
    machine=ibmrs6000 opsys=aix4-2
  ;;

I have confirmed that this modification makes the build work properly now.

If someone could commit these three lines to the configure.in file and
run autoconf to update the configure script distributed with Emacs, that
would be great.

-Dan