Clang's preprocessor may emit extra spaces for lines starting with '#'.
Lines with these extra characters cannot be handled by Kconfig and will
be ignored with warnings like,
unexpected data: # CONFIG_OF_BOARD_FIXUP is not set
Those options that is expected to be assigned explicitly with N will be
set to the default value, messing up board configurations.
Let's sed these spaces away to ensure board configurations could be
correctly generated with Clang.
Link: https://github.com/llvm/llvm-project/issues/78778
Fixes: 2027e99e61 ("Makefile: Run defconfig files through the C preprocessor")
Reported-by: Nathaniel Hourt <I@nathaniel.land>
Signed-off-by: Yao Zi <ziyao@disroot.org>
252cd20530