build: have config-clean deal with old temp files

This is a temporary commit to have 'make config-clean' remove
temporary files from the previous scripts/config version.

The .gitignore file is updated to deal with the old files as well.

Cc: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
Signed-off-by: Eneas U de Queiroz <cotequeiroz@gmail.com>

scripts/config/.gitignore

@@ -12,3 +12,10 @@ mconf
 nconf
 qconf
 gconf
+
+#
+# temporary files from older version.  Should be removed
+#
+zconf.???.c
+zconf.hash.c
+.tmp_qtcheck

scripts/config/Makefile

@@ -7,7 +7,10 @@ all: conf mconf
 clean:
 	rm -f *.o lxdialog/*.o *.moc $(clean-files) conf mconf qconf
 
-clean-files	:=
+# This clean-files definition is here to ensure that temporary files from the
+# previous version are removed by make config-clean.
+# It should be removed or emptied when this Makefile get updated again.
+clean-files	:= zconf.tab.c zconf.lex.c zconf.hash.c .tmp_qtcheck
 
 # ===========================================================================
 # Variables needed by the upstream Makefile