=== modified file 'configure.ac'
--- configure.ac	2014-05-29 23:13:32 +0000
+++ configure.ac	2014-05-30 10:28:04 +0000
@@ -1975,6 +1975,8 @@
 case "$opsys" in
   ## darwin ld insists on the use of malloc routines in the System framework.
   darwin|mingw32|sol2-10) system_malloc=yes ;;
+  ## experimental
+  aix4-2) system_malloc=yes ;;
 esac
 
 GMALLOC_OBJ=

=== modified file 'src/lisp.h'
--- src/lisp.h	2014-05-30 07:40:29 +0000
+++ src/lisp.h	2014-05-30 10:28:04 +0000
@@ -72,7 +72,7 @@
    2.  We know malloc returns a multiple of 8.  */
 #if (defined alignas \
      && (defined GNU_MALLOC || defined DOUG_LEA_MALLOC || defined __GLIBC__ \
-	 || defined DARWIN_OS || defined __sun || defined __MINGW32__))
+	 || defined DARWIN_OS || defined __sun || defined _AIX || defined __MINGW32__))
 # define NONPOINTER_BITS 0
 #else
 # define NONPOINTER_BITS GCTYPEBITS