Index: system.h
===================================================================
--- system.h    (revision 193623)
+++ system.h    (working copy)
@@ -228,6 +228,9 @@
 # include <stdlib.h>
 #endif

+/* Undef vec_free from AIX stdlib.h header which conflicts with vec.h.  */
+#undef vec_free
+
 /* If we don't have an overriding definition, set SUCCESS_EXIT_CODE and
    FATAL_EXIT_CODE to EXIT_SUCCESS and EXIT_FAILURE respectively,
    or 0 and 1 if those macros are not defined.  */