make: config -- Drop try-build helper

Don't need it, also add DEFINES into try-cc,
after all we define a number of things in
this variable and it's better to pass it
to tests for conditional compilation.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Tested-by: Ruslan Kuprieiv <kupruser@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>