[U-Boot] idirafter causes host sha256.h to be included

[Jeroen Hofstee]

Hello,

tools/Makefile uses the following substitution

HOST_EXTRACFLAGS += -include $(srctree)/include/libfdt_env.h \
		$(patsubst -I%,-idirafter%, $(UBOOTINCLUDE)) \
		...

Which adds -idirafterinclude when compiling image-fit.c. Since
mentioned file includes sha256.h, which is a system include on FreeBSD,
the system version is included instead of the intended U-boot
include/sha256.h and building fails. Without the substitution it builds
successfully.

What is the intention of using idirafter?

Regards,
Jeroen