kconfig: do not hardcode "include/config/auto.conf" filename

Regardless of KCONFIG_AUTOCONFIG, the filename written as a Make target
into "include/config/auto.conf.cmd" was always the default one.

Of course this doesn't make it work for the Kernel kbuild system, since
there the filename is hardcoded at several places in the Makefiles.

Signed-off-by: Markus Heidelberg <markus.heidelberg@web.de>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index 4a9af6f..f379b0b 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -74,6 +74,7 @@
 
 /* confdata.c */
 const char *conf_get_configname(void);
+const char *conf_get_autoconfig_name(void);
 char *conf_get_default_confname(void);
 void sym_set_change_count(int count);
 void sym_add_change_count(int count);