AIX patches from Andreas.

doc/FAQ_AIX

@@ -12,8 +12,7 @@ if you have readline or libz there:
 libpq++ does not work because xlC does not have the string and bool classes.
 compiling the few files, that fail, with g++ does work.
 
-Compiling PostgreSQL with gcc (2.95.2) on AIX does work if you use the
-configure option: --with-template=aix_gcc 
+Compiling PostgreSQL with gcc (2.95.2) on AIX also works.
 
-There will probably be warnings about int8 - int64 redefines and 0.0/0.0
-devision warnings, which you can safely ignore.
+There will probably be warnings about int8 - int64 redefines, 0.0/0.0
+division and duplicate symbol warnings which you can safely ignore.

src/template/aix

 if test "$GCC" = yes ; then
-  CFLAGS=-pipe
+  CFLAGS='-O2 -pipe'
 else # not GCC
+  CFLAGS='-O2 -qmaxmem=16384 -qsrcmsg -qlonglong'
   case $host_os in
-    aix3.2.5)
-      CFLAGS='-qchars=signed -qmaxmem=8192 -qhalt=w -qsrcmsg'
-      ;;
-    aix4.1)
-      CFLAGS='-qchars=signed -qmaxmem=8192 -qhalt=w -qsrcmsg -qcheck=divzero'
-      ;;
-    aix4.2 | aix4.3)
-      CFLAGS='-qmaxmem=16384 -qhalt=w -qsrcmsg -qlanglvl=extended -qlonglong'
-      ;;
+    aix3.2.5 | aix4.1*)
+      CFLAGS='-qmaxmem=16384 -qsrcmsg' ;;
   esac
 fi # not GCC