* Remove SPEC declarations from mk/spec
* Remove all board-specific REQUIRE declaratiions left
* Replace [have_spec <board>] run-script declarations with have_board where necessary
* Remove addition of BOARD variable to SPECS in toplevel Makefile
* Move board-specific directories in base-hw out of specs
* get rid of alarm abstraction
* get rid of Timeout::Time type
* get rid of pointer arguments
* get rid of _discard_timeout indirection
* get rid of 65th bit in stored time values
* get rid of Timeout_scheduler interface
* get rid of uninitialized deadlines
* get rid of default arguments
* get rid of Timeout::_periodic
* get rid of Timeout::Raw
* use list abstraction
* only one interface for timeout handlers
* rework locking scheme to be smp safe
* move all method definitions to CC file
* name mutexes more accurate
* fix when & how to set time-source timeout
* fix deadlocks
Fixes#3884
Since the timer and timeout handling is part of the base library (the
dynamic linker), it belongs to the base repository.
Besides moving the timer and its related infrastructure (alarm, timeout
libs, tests) to the base repository, this patch also moves the timer
from the 'drivers' subdirectory directly to 'src' and disamibuates the
timer's build locations for the various kernels. Otherwise the different
timer implementations could interfere with each other when using one
build directory with multiple kernels.
Note that this patch changes the include paths for the former os/timer,
os/alarm.h, os/duration.h, and os/timed_semaphore.h to base/.
Issue #3101
