This commit introduces the changes needed in the port build system that
will allow us to compile ports with Clang. Note that many ports still
don't build, especially due to linker differences. Fixing these is
outside the scope of this PR.
For now, building bash, ncurses and nano is known to work. Bash runs
fine, while nano crashes due to DT_VERSYM not being supported by our
dynamic loader.
- SERENITY_ROOT is being kept around for compatibility reasons, and will
be removed gradually
- SERENITY_INSTALL_ROOT points to DESTDIR but will be preferred over
that in the future
- SERENITY_SOURCE_DIR points to the root folder of the repository. Let's
keep the root terminology in the directory structure sort of sense out
of here
install-ports copys the necessary files from Ports/ to /usr/Ports. Also
refactor the compiler and destiation variables from .port_include.sh
into .hosted_defs.sh. .hosted_defs.sh does not exists when ports are
built in serenity
