Enhance Makefiles; use sieve.lds

Use an extra group for deepcl targets. Remove some naive/ targets.

Fix the sieve.lds so that it even builds a smaller executable than without.
The SIZEOF_HEADERS was missing and putting __tls after .bss seems to have
caused it to be align on a page boundary, sounds logical.

Add measurements of L1d misses from cachegrind of single-threaded
applications.