Remove Ada-specific configuration options

[Sebastian Huber]

We have currently three Ada related configuration options:

• CONFIGURE_GNAT_RTEMS

• CONFIGURE_MAXIMUM_ADA_TASKS

• CONFIGURE_MAXIMUM_FAKE_ADA_TASKS

The CONFIGURE_MAXIMUM_FAKE_ADA_TASKS option has no effect. The CONFIGURE_GNAT_RTEMS is mandatory to use the CONFIGURE_MAXIMUM_ADA_TASKS option. So, if you just use

#define CONFIGURE_MAXIMUM_ADA_TASKS 123

then you get a re-definition warning and hopefully pay attention to it. This is not very user friendly from point of view.

The CONFIGURE_MAXIMUM_ADA_TASKS just adds the configured count to CONFIGURE_MAXIMUM_POSIX_THREADS.

The original purpose of these was to:

CONFIGURE_GNAT_RTEMS - add in resources required by Ada run-time independent
of the number of Ada tasks (e.g. POSIX threads)

CONFIGURE_MAXIMUM_ADA_TASKS - add in POSIX threads, condition variable,
and mutex required for each Ada task

CONFIGURE_MAXIMUM_FAKE_ADA_TASKS - add in condition variables and mutex
required by Ada run-time for a task/thread created outside the Ada run-time which
invokes Ada code and is thus a user of the run-time.

Given that you can turn on unlimited threads now and condition variables and mutexes
are static, I don't think they have a need any longer. Plus it sounds like they bit rotted.
If we needed them still, they would have to be fixed.

We still need documentation that Ada tasks are POSIX threads and must be accounted
for in configuring the system. So when moving documentation around, please make that
point clear in the CONFIGURE_MAXIMUM_POSIX_THREADS description.

See also:

​https://lists.rtems.org/pipermail/devel/2019-December/056523.html

[Sebastian Huber <sebastian.huber@…>]

In [changeset:"88c198bfae6572fe7780c3bf5f3a59b981ed5f55/rtems" 88c198b/rtems]:

config: Remove Ada configuration options

Update #3845.

[Sebastian Huber <sebastian.huber@…>]

In [changeset:"da309b93deb2edf0255108f90d9bbd010eb79e12/rtems-docs" da309b9/rtems-docs]:

c-user: Remove Ada configuration options

Close #3845.

[Sebastian Huber <sebastian.huber@…>]

In [changeset:"51fd6b47b1346d8491843b17a7745ec049cb0d56/rtems" 51fd6b4/rtems]:

config: Fix CONFIGURE_MAXIMUM_POSIX_THREADS

Bug was introduced by previous commit.

Update #3845.