hake: Ensure correct symbols get linked

Signed-off-by: Lukas Humbel <lukas.humbel@inf.ethz.ch>

hake: Make proper use of lib dependencies

Library dependencies are not put anymore into archive file, but
assembled when the application is linked.

Signed-off-by: Lukas Humbel <lukas.humbel@inf.ethz.ch>

libc: removing newlib, adding BSD libc
posixcompat: moving gettimeofday to libc
harness: adding a simple math test
lwip, lwip2: moving includes to /include, compiling with BSD headers

Signed-off-by: Adam Turowski <adam.turowski@inf.ethz.ch>