Build only changes

[Alexnader Kuleshov]

Hello All,

I'm new in FreeBSD, so my question can be stupid, but I have just executed
`make buildworld` and it was successful. Now I want to do some little changes
for example in one of `usr.sbin` application. How can I recompile only changed
application? If I'm executing `make buildworld` again, I see that there is
new long-long-time compilation of the full base.

I've started to look into the base's Makefiles and tried to execute:

make buildworld -j4 -DMK_CDDL=no -DMK_KERBEROS=no -DMK_RESCUE=no -DMK_CRYPT=no
-DMK_TEST=no -DNO_CLEAN=yes -DMK_CLANG_BOOTSTRAP=no -DMK_CLANG=no

but anyway I see that contrib/llvm/tools/clang/* is compiling.

Is there ability to compile only one separate dir in the FreeBSD base?

Thank you.