Let's not leak details from src/shared and src/libsystemd into
src/basic, even though you can't actually do anything useful with
just forward declarations from src/shared.
The sd-forward.h header is put in src/libsystemd/sd-common as we
don't have a directory for shared internal headers for libsystemd
yet.
Let's also rename forward.h to basic-forward.h to keep things
self-explanatory.
Let's keep macro.h for the extremely generic macros that don't fit anywhere
else. Since CLEANUP_ARRAY() is already in memory-util-fundamental.h, we can
make a good case for moving the other cleanup macros in there as well.
Daan De Meyer
Yu Watanabe