configure: add possibility to set arbitrary variable in check_for

If check_for is able to find the required prog/inc/lib, allow it to
set an arbitrary variable to 'y'. This variable is then pushed down
to the kconfig definition.

For example:
  has_or_abort prog=foobar kconfig=has_foobar

If foobar is available, it yields a kconfig variable defaulting to y:
    config CONFIGURE_has_foobar
        bool
        default y

If foobar is missing, it yields a kconfig variable defaulting to n:
    config CONFIGURE_has_foobar
        bool

Thus it is possible to depends on that variabel to show/hide options:
    config SOME_FEATURE
        bool
        prompt "Some feature"
        depends on CONFIGURE_has_foobar

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

1 files changed, 1 insertions, 0 deletions

diff --git a/.hgignore b/.hgignore
index a8b6e234..d39c8bdb 100644
--- a/.hgignore
+++ b/.hgignore
@@ -13,6 +13,7 @@ kconfig/conf
 kconfig/?conf
 kconfig/**.o
 kconfig/**.dep
+config/configure.in
 config.gen/
 .config
 .config.2