Add cmake -DINIT_CONFIG= option that can point at any initial file.
"make clean" does not delete .config any more.
Note reconfiguration does NOT causes recompilation because -imacros
hides the generated .h from CMake's dependency scan. This is not a
regression, that problems exists since -imacros was introduced. At least
it's now possible to "make clean" and rebuild without losing the .config
file.
Fix for #3617
Signed-off-by: Marc Herbert <marc.herbert@intel.com>
When there are changes made to Kconfig files it's better
to run olddefconfig automatically to prevent undesired behaviour,
like for example depending on added config that has some default value
that is not present because developer didn't run olddefconfig
after pulling changes.
Signed-off-by: Janusz Jankowski <janusz.jankowski@linux.intel.com>