[CRIU] [PATCH v5 0/5] make: build improvements

[Kinsbursky Stanislav]

This patch set:
1) Moves syscalls-related files to separated directory.
2) Moves pie-related files to separated directory.
3) Rework and dramatically simplifies pie build.
4) Done a small cleanup to generic Makefile.inc

v2:
1) Better patches comments
2) Rename-aware diffs in patches

v3:
1) Fixed parasite build.
2) Fixed blobs deps - %.bin and %.bin.o can now be build in parallel.
3) Updated restorer link: restorer is not linked with util-net.o anymore.

v4:
1) util-net.c left in root dir.
2) "syscall" was renamed into "x86_64" and now build as $(ARCH) target.
3) Makefile.inc was removed and it's content become a part of main Makefile.

v5:
1) "syscall" was moved to "arch/x86/" directory.