smptests: Be successful on one processor
score: Include missing header files
posix: Include missing header files
network: Include missing header file
shell: Include missing header file
testsuites: Include missing header files
score: Use _Thread_Get_executing()
rtems: Use _Thread_Get_executing()
posix: Use _Thread_Get_executing()
testsuites: Use _Thread_Get_executing()
libcsupport: Use _Thread_Get_executing()
libmisc: Use _Thread_Get_executing()
score: Move ISR level content to single file
score: Move ISR catch support functions

Delete now unused file <rtems/score/isr.inl>.
score: Add and use _ISR_Get_nest_level()
sapi: Add rtems_configuration_is_smp_enabled()

Add a configuration field which indicates if the SMP mode of operation
is enabled.  This can be used to disable features unsupported on SMP,
e.g task variables.
rtems: Error for task delete on SMP

Task deletion is currently not implemented on SMP configurations.
rtems: Error for task variables on SMP

Task variables are not supported on SMP.
score: Error for non-preemptible tasks on SMP

A common use case for disabled preemption was to ensure mutual exclusion
on single-processor configurations.  On SMP this does not work.

To abandon non-preemptible tasks simplifies the scheduler.
posix: Create semaphore implementation header

Move implementation specific parts of semaphore.h and semaphore.inl into
new header file semaphoreimpl.h.  The semaphore.h contains now only the
application visible API.