If I download the fresh buildroot (as of 2024), I can see that when I don’t explicitly select the option to build with u-boot, on running make help I will not see anything related to u-boot. On the other hand, if I run menuconfig and select u-boot, I will see the u-boot related configuration options. How does this mechanism work?

P. S.: I see the if/endif part in Config.in located at /boot/uboot. But how does the Makefile include a new dynamic target for this package? It is still not known to me..

P. P. S.: I would ideally like to study how it is done with u-boot so I can do the same thing for my packages.