kconfig: integrate split config into silentoldconfig

Now that kconfig can load multiple configurations, it becomes simple to
integrate the split config step, by simply comparing the new .config file with
the old auto.conf (and then saving the new auto.conf).  A nice side effect is
that this saves a bit of disk space and cache, as no data needs to be read
from or saved into the splitted config files anymore (e.g.  include/config is
now 648KB instead of 5.2MB).

Signed-off-by: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

scripts/kconfig/expr.h

@@ -65,6 +65,7 @@ enum symbol_type {
 
 enum {
 	S_DEF_USER,		/* main user value */
+	S_DEF_AUTO,
 };
 
 struct symbol {
@@ -97,7 +98,7 @@ struct symbol {
 #define SYMBOL_WARNED		0x8000
 #define SYMBOL_DEF		0x10000
 #define SYMBOL_DEF_USER		0x10000
-#define SYMBOL_DEF2		0x20000
+#define SYMBOL_DEF_AUTO		0x20000
 #define SYMBOL_DEF3		0x40000
 #define SYMBOL_DEF4		0x80000