Working on CRIU Makefilest feels like walking on a minefield.
This is not an attempt to demine it, but to make some mines
a bit easier to notice.

OK, this is what we're trying to do here:

1. Drop the $(SRC_DIR)/ prefix from the target: as this is a top-level
   Makefile, we can just use paths relative to top-level source  dir.

2. Drop the $(SRC_DIR) from the symlink, use relative one. Relative
   symlinks are always better -- say, if a source directory is
   moved, everything will still work.

3. The "compel/include/asm: compel/arch/$(ARCH)/src/lib/include"
   dependency is useless. Yes, the left side is created as a symlink
   to the right side, but that doesn't mean that "make" should
   compare the timestamps of both to decide whether to remake
   the target.

4. The "$(COMPEL_VERSION_HEADER): compel/include/asm" dependency
   is wrong, the compel/include/asm symlink is not needed for
   $(COMPEL_VERSION_HEADER) generation. Remove it.

5. Move compel/plugins/std.built-in.o prerequisite from the rule
   to compel-plugins variable, and use it.

travis-ci: success for More polishing for compel cli
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>