depot/build creates target directory with missing dependencies

[Guido Witmond]

Hi Genodians,


I think I start to get the hang of the depot system. However, I get this 
behaviour with missing depencencies:

$ tool/depot/create guido/src/feather
created guido/src/feather/2018-07-04-c

$ tool/depot/build guido/bin/x86_64/feather/2018-07-04-c KEEP_BUILD_DIR=1
...
Library description file libc_lwip.mk is missing
Library description file libc_lwip_nic_dhcp.mk is missing
created guido/bin/x86_64/feather/2018-07-04-c

But that directory is completely empty.

Running the command a second time give me:

make[1]: Nothing to be done for 'all'.

As there are missing dependencies, I'd expect the second run to give the 
same error as the first run, not a message that everything is fine. To 
retry I currently rm -r depot/guido and create and build again or add 
the REBUILD=1 flag.

My questions:
- How can I add these lwip-libraries included? I don't see any examples 
of these included in used_apis.
- What's going wrong that it mentions the missing deps but still creates 
the target directory?

Cheers, Guido