kconfig: add savedefconfig

savedefconfig will save a minimal config to a file
named "defconfig".

The config symbols are saved in the same order as
they appear in the menu structure so it should
be possible to map them to the relevant menus
if desired.

The implementation was tested against several minimal
configs for arm which was created using brute-force.

There was one regression related to default numbers
which had their valid range further limited by another symbol.

Sample:

config FOO
	int "foo"
	default 4

config BAR
	int "bar"
	range 0 FOO

If FOO is set to 3 then BAR cannot take a value higher than 3.
But the current implementation will set BAR equal to 4.

This is seldomly used and the final configuration is OK,
and the fix was non-trivial.
So it was documented in the code and left as is.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Michal Marek <mmarek@suse.cz>

1 files changed, 1 insertions, 0 deletions

diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index 755b8190eb64..76db065ed72c 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -127,6 +127,7 @@ void sym_clear_all_valid(void);
 void sym_set_all_changed(void);
 void sym_set_changed(struct symbol *sym);
 struct symbol *sym_choice_default(struct symbol *sym);
+const char *sym_get_string_default(struct symbol *sym);
 struct symbol *sym_check_deps(struct symbol *sym);
 struct property *prop_alloc(enum prop_type type, struct symbol *sym);
 struct symbol *prop_get_symbol(struct property *prop);