This is probably my fault but when I

make obj
make build

In usr.bin/apropos I get

cc -O2  -Wall -Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith
-Wno-uninitialized -Werror   -I/usr/src/usr.bin/apropos/../man -c
/usr/src/usr.bin/apropos/apropos.c
cc -O2  -Wall -Wstrict-prototypes -Wmissing-prototypes -Wpointer-arith
-Wno-uninitialized -Werror   -I/usr/src/usr.bin/apropos/../man -c
/usr/src/usr.bin/apropos/../man/config.c
cc   -o /usr/src/usr.bin/apropos/../man/apropos apropos.o config.o 
/usr/bin/ld: cannot open output file
/usr/src/usr.bin/apropos/../man/apropos: Is a directory
collect2: ld returned 1 exit status

What did I do wrong?

--Andrew