Switch to using maintainer-clean to clean autotools files.

Makefile.am

@@ -7,15 +7,13 @@ bgpq4_SOURCES=bgpq4.c sx_report.c bgpq_expander.c sx_slentry.c \
 dist_doc_DATA=bgpq4.html
 dist_man8_MANS=bgpq4.8
 EXTRA_DIST=bootstrap readme.header README.md CHANGES COPYRIGHT bgpq4.spec
+CLEANFILES=bgpq4.html
+MAINTAINERCLEANFILES=configure aclocal.m4 compile \
+                     install-sh missing Makefile.in depcomp \
+                     stamp-h1 config.h.in
 
 bgpq4.html: readme.header README.md
 	cat readme.header README.md | @MARKDOWN@ > bgpq4.html
 
-clean-local:
-	-rm config.status configure config.log
-	-rm Makefile
-	-rm -r autom4te.cache/
-	-rm aclocal.m4
-	-rm compile install-sh missing Makefile.in depcomp stamp-h1
-	-rm config.h config.h.in
-
+maintainer-clean-local:
+	-rm -rf autom4te.cache

README.md

@@ -374,7 +374,7 @@ In order to compile the software, run:
 If you wish to remove the generated build system files from your
 working tree, run:
 
-    make clean-local
+    make maintainer-clean
 
 
 SEE ALSO