Index: tools/build/v2/engine/mem.h
===================================================================
--- tools/build/v2/engine/mem.h	(revision 80066)
+++ tools/build/v2/engine/mem.h	(working copy)
@@ -65,6 +65,7 @@
 #else
 
     /* Standard C memory allocation. */
+    #include <stdlib.h>
     #define bjam_malloc_x(s) malloc(s)
     #define bjam_calloc_x(n,s) calloc(n,s)
     #define bjam_realloc_x(p,s) realloc(p,s)