Generate codlist.c only when MAINTAINER_MODE

The user is not supposed to regenerate .c files.  In addition, the
generation rule is subtly nonportable (it depends on whether or not
'#' can be escaped in Makefiles, an issue that does not appear
settled.)

support/Makefile.codelets

@@ -5,6 +5,13 @@
 CODLIST = codlist.c
 CODELET_NAME=codelet_
 
+# only delete codlist.c in maintainer-mode, since it is included in the dist
+# FIXME: is there a way to delete in 'make clean' only when builddir != srcdir?
+maintainer-clean-local:
+	rm -f $(CODLIST)
+
+if MAINTAINER_MODE
+
 # rule to build codlist
 $(CODLIST): Makefile
 	(									\
@@ -31,13 +38,6 @@ $(CODLIST): Makefile
 	echo "};";								\
 	) >$@
 
-# only delete codlist.c in maintainer-mode, since it is included in the dist
-# FIXME: is there a way to delete in 'make clean' only when builddir != srcdir?
-maintainer-clean-local:
-	rm -f $(CODLIST)
-
-if MAINTAINER_MODE
-
 #INDENT = indent -kr -cs -i5 -l800 -fca -nfc1 -sc -sob -cli4 -TR -Tplanner -TV
 TWOVERS = sh ${top_srcdir}/support/twovers.sh
 GENFFTDIR = ${top_builddir}/genfft