make: Use -iquote for headers lookup

Some of ours headers (such as syscall.h) are
clashes with system headers names. So we need
to be sure that the headers we include as

 | #include "something.h"

being searched in known place. In particular on
some machines it it already produced problems.

This btw revealved a problem in cr-dump.c -- we've
had #include <parasite.h> there. Fix it.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Tested-by: Andrew Vagin <avagin@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>