Make a brk/sbrk emulation.

Mac OS X seems to have some difficulties with brk/sbrk (maybe with the
4MB heap limit), and replace all the allocation logic will be prone to
errors, I'll add a new define and lib to emulate brk/sbrk using more
standard allocation methods. By default the heap is 64MB, it should be
enough.

util/ncgg/pmfile

@@ -51,7 +51,8 @@ tool_ncgg = cprogram {
 	},
 	
 	lib_em_data,
-	
+	lib_sbrk,
+
 	outputs = {"%U%-ncgg"},
 	install = pm.install(TOOLDIR.."ncgg")
 }