Makefile: -O3 and debug build
Makefile: -O3 and debug build

Build standard builds with -O3.
Add a "debug" target with -Og and asan.

Change-Id: Ie943babb808ffdb1d807bcd7ce4ace54723b49a9

osmocom/osmo-tetra,osmocom/osmo-tetra,osmocom/osmo-tetra