diff --git a/make/autoconf.mk b/make/autoconf.mk
index 0b05a3ec..19db1843 100644
--- a/make/autoconf.mk
+++ b/make/autoconf.mk
@@ -4,9 +4,9 @@
 # $Id$
 
 CONFIG_ACDONE := $(wildcard config.acdone)
-CLEAN += $(wildcard *.acdone)
+CLEAN = $(wildcard *.acdone)
 DISTCLEAN += configure config.log autoscan.log configure.ac config.status
-AC_FILES_IN = $(shell find . -name '*.in' | grep -ve "contrib\|dist\|nomake")
+AC_FILES_IN = $(shell find . -name '*.in' -maxdepth 2 | grep -ve "contrib\|dist\|nomake")
 AC_FILES    = $(basename $(AC_FILES_IN))
 
 all: config $(AC_FILES)