CONFIG_SPL_BUILD seems to be not defined in my u-boot-spl program.. why?

[Chan Kim]

Dear u-boot experts,

While analyzing u-boot-spl program on qemu arm64 virtual machine, I'm seems
the program counter skips part of a code and it seems the reason is that
CONFIG_SPL_BUILD is not defined. But I'm running spl/u-boot-spl and the
spl/u-boot.cfg file contains 'CONFIG_SPL_BUILD=1'. In what case can this
happen?
Any comment will be deeply appreciated.
Thank you.

Chan Kim