Mine

make -V CFILES -V SYSTEM_CFILES -V GEN_CFILES |  MKDEP_CPP="cc -E" CC="cc" xargs mkdep -a -f .newdep -O2 -pipe -funroll-loops -ffast-math -fno-strict-aliasing -march=pentiumpro -Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes  -Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual  -fformat-extensions -std=c99 -g -nostdinc -I-  -I. -I/usr/src/sys -I/usr/src/sys/contrib/altq -I/usr/src/sys/contrib/ipfilter -I/usr/src/sys/contrib/pf -I/usr/src/sys/dev/ath -I/usr/src/sys/contrib/ngatm -I/usr/src/sys/dev/twa -D_KERNEL -DHAVE_KERNEL_OPTION_HEADERS -include opt_global.h -fno-common -finline-limit=8000 --param inline-unit-growth=100 --param large-function-growth=1000  -mno-align-long-strings -mpreferred-stack-boundary=2  -mno-mmx -mno-3dnow -mno-sse -mno-sse2 -ffreestanding
/usr/src/sys/pci/if_xl.c:143:23: miibus_if.h: No such file or directory
mkdep: compile failed
*** Error code 1

Stop in /usr/obj/usr/src/sys/MYKERNEL.
*** Error code 1

Stop in /usr/src.
*** Error code 1

Stop in /usr/src.