--- a/Makefile
+++ b/Makefile
@@ -39,16 +39,20 @@ ifdef PR_CLIENT_BUILD
 export::
 	rm -r -f $(DIST)/../public/nspr
 ifdef PR_CLIENT_BUILD_UNIX
 	rm -f $(DIST)/lib/libnspr.a
 	rm -f $(DIST)/bin/libnspr.$(DLL_SUFFIX)
 endif
 endif
 
+distclean::
+	@echo "cd pr/tests; $(MAKE) $@"
+	@$(MAKE) -C pr/tests $@
+
 release::
 	echo $(BUILD_NUMBER) > $(RELEASE_DIR)/$(BUILD_NUMBER)/version.df
 	@if test -f imports.df; then \
 	    echo "cp -f imports.df $(RELEASE_DIR)/$(BUILD_NUMBER)/imports.df"; \
 	    cp -f imports.df $(RELEASE_DIR)/$(BUILD_NUMBER)/imports.df; \
 	else \
 	    echo "echo > $(RELEASE_DIR)/$(BUILD_NUMBER)/imports.df"; \
 	    echo > $(RELEASE_DIR)/$(BUILD_NUMBER)/imports.df; \

--- a/Makefile.in
+++ b/Makefile.in
@@ -26,16 +26,18 @@ include $(MOD_DEPTH)/config/autoconf.mk
 
 DIRS = config pr lib
 
 ifdef MOZILLA_CLIENT
 PR_CLIENT_BUILD = 1
 PR_CLIENT_BUILD_UNIX = 1
 endif
 
+DIST_GARBAGE = config.cache config.log config.status
+
 include $(topsrcdir)/config/rules.mk
 
 #
 # The -ll option of zip converts CR LF to LF.
 #
 ifeq ($(OS_ARCH),WINNT)
 ZIP_ASCII_OPT = -ll
 endif
@@ -44,16 +46,22 @@ ifdef PR_CLIENT_BUILD
 export::
 	rm -r -f $(DIST)/../public/nspr
 ifdef PR_CLIENT_BUILD_UNIX
 	rm -f $(DIST)/lib/libnspr.a
 	rm -f $(DIST)/bin/libnspr.$(DLL_SUFFIX)
 endif
 endif
 
+# Delete config/autoconf.mk last because it is included by every makefile.
+distclean::
+	@echo "cd pr/tests; $(MAKE) $@"
+	@$(MAKE) -C pr/tests $@
+	rm -f config/autoconf.mk
+
 release::
 	echo $(BUILD_NUMBER) > $(RELEASE_DIR)/$(BUILD_NUMBER)/version.df
 	@if test -f imports.df; then \
 	    echo "cp -f imports.df $(RELEASE_DIR)/$(BUILD_NUMBER)/imports.df"; \
 	    cp -f imports.df $(RELEASE_DIR)/$(BUILD_NUMBER)/imports.df; \
 	else \
 	    echo "echo > $(RELEASE_DIR)/$(BUILD_NUMBER)/imports.df"; \
 	    echo > $(RELEASE_DIR)/$(BUILD_NUMBER)/imports.df; \

--- a/config/Makefile.in
+++ b/config/Makefile.in
@@ -22,16 +22,20 @@ topsrcdir	= @top_srcdir@
 srcdir		= @srcdir@
 VPATH		= @srcdir@
 
 include $(MOD_DEPTH)/config/autoconf.mk
 
 # Indicate that this directory builds build tools.
 INTERNAL_TOOLS	= 1
 
+# autoconf.mk must be deleted last (from the top-level directory)
+# because it is included by every makefile.
+DIST_GARBAGE	= nsprincl.mk nsprincl.sh
+
 include $(topsrcdir)/config/config.mk
 
 CSRCS	= nsinstall.c now.c
 
 PLSRCS	= nfspwd.pl
 
 ifeq ($(OS_ARCH), WINNT)
 PROG_SUFFIX = .exe

--- a/config/config.mk
+++ b/config/config.mk
@@ -70,16 +70,20 @@ endif
 endif
 
 ifdef BUILD_DEBUG_GC
 DEFINES		+= -DDEBUG_GC
 endif
 
 GARBAGE		+= $(DEPENDENCIES) core $(wildcard core.[0-9]*)
 
+ifdef USE_AUTOCONF
+DIST_GARBAGE += Makefile
+endif
+
 DEFINES += -DFORCE_PR_LOG
 
 ifeq ($(_PR_NO_CLOCK_TIMER),1)
 DEFINES += -D_PR_NO_CLOCK_TIMER
 endif
 
 ifeq ($(USE_PTHREADS), 1)
 DEFINES += -D_PR_PTHREADS -UHAVE_CVAR_BUILT_ON_SEM

--- a/config/rules.mk
+++ b/config/rules.mk
@@ -188,16 +188,20 @@ clean::
 clobber::
 	rm -rf $(OBJS) $(TARGETS) $(filter-out . ..,$(OBJDIR)) $(GARBAGE) so_locations $(NOSUCHFILE)
 	+$(LOOP_OVER_DIRS)
 
 realclean clobber_all::
 	rm -rf $(wildcard *.OBJ *.OBJD) dist $(ALL_TRASH)
 	+$(LOOP_OVER_DIRS)
 
+distclean::
+	rm -rf $(wildcard *.OBJ *.OBJD) dist $(ALL_TRASH) $(DIST_GARBAGE)
+	+$(LOOP_OVER_DIRS)
+
 release:: export
 ifdef RELEASE_BINS
 	@echo "Copying executable programs and scripts to release directory"
 	@if test -z "$(BUILD_NUMBER)"; then \
 		echo "BUILD_NUMBER must be defined"; \
 		false; \
 	else \
 		true; \