equeue: align passed-in buffer ...

Make equeue_create_inplace align the passed-in buffer and size to
sizeof(void *).

Really we should be aiming to align more for ARM, as blocks should be
8-byte aligned, but the internal heap mechanisms only work to 4-byte
alignment at the moment. More work would be needed to ensure 8-byte
alignment of allocated blocks.

events.shared-eventsize: increased from 256B to 768B ...

Original value was too small once both ESP8266 driver and
asynchronous DNS started to use shared event queue. An assumption is
made that once shared event queue is taken into use there are going to
be multiple users instead of one, for which the original value would
have been sufficient.

Edit README.md ...

Edit file, mostly for active voice.

Increases events.shared-stacksize to 2K ...

ESP8266 driver started to use global event queue to handle some AT
parsing and call Socket::sigio() events. It turned out that when
running DNS tests, or Pelion Client, the stack space (1kB) is not
enough for the purpose.

Therefore we propose that this is raised to 2kB, as the assumption
is that event loop should allow as equivalently complex code than
any other threads.

In Mbed OS, the default Thread stack size is 4kB, but we assume 2kB
to be enough for non-blocking event purposes.

Merge pull request #9066 from deepikabhavnani/equeue_chain_fixed ...

Equeue chaining bug fixes

Added test case for verification

Corrected destructor loop to clear all pending events ...

In `equeue_destroy` the external loop was for main events linked
list and internal loop for siblings.
Siblings start was not initialized correctly for each main link

Old pointers of sibling were not cleared ...

When adding sibling at the head of linked list, the head if pointing
to something in linked list was not updated, hence a loop was formed
in linked list

Element0 - First addition to linked list
Element1 - Has higher delay hence added to back
0 ->(next) 1
Element2 - Delay is same as Element0, hence should be sibling of 0
           Shall be added at head

Expected:
2    ------------->(next) 1
|(sibling)
0

Bug: (Resolved with this)
2    ------------->(next) 1
|(sibling)
0    ------------->(next) 1

If we add more elements and next pointer of sibling is updated, old
references will cause issues
Element3 added

Expected:
2    ------------->(next) 3  ------------->(next) 1
|(sibling)
0

Bug: (Resolved with this)
2    ------------->(next) 3  ------------->(next) 1
|(sibling)
0    ------------->(next) 1
***Both siblings here point to different next***

Return error in case chaining fails

Memory allocated from parent queue was freed/added to chained queue. ...

Issue was seen with below example
EventQueue q1;
EventQueue q2;

void main() {
while( true ) {
q1.chain( &q2 ); // Chain q2 to q1
q1.chain( NULL ); // Remove chain from q1
//This second step should free the memory from the chained q2 event.
}
}

Memory allocated from q1 slab was freed for q2, which will result in
memory leak.

Check is allocation in event queue was success or not, and ...

report error / assert when allocation fails.

events: add spdx license

MBED_NO_GLOBAL_USING_DIRECTIVE is added to remove auto-addition of namespace ...

Macro guard `MBED_NO_GLOBAL_USING_DIRECTIVE` is added around namespace, to avoid
polluting users namespace.

events: fix coding style

events: fix events coding style

Merge pull request #8652 from 0xc0170/dev_rollup ...

Rollup PR for docs

feat: Add name to shared queue threads

Fix typos in Events doxygen

Merge pull request #8365 from 0xc0170/fix_astyle_common2 ...

Fix astyle for tests folders

Merge pull request #7864 from deepikabhavnani/remove_mbed_h ...

Add required header file and namespace element instead add all.

events: fix astyle

EventQueue documentation fix.

EventQueue: Add required header file and namespace element instead add all

Remove protected class from EventQueue Doxy

Merge pull request #7810 from kegilbert/eventqueue-templatewall-rework ...

Eventqueue Templatewall Doxygen Rework

Copy edit EventQueue.h ...

Copy edit file for consistent capitalization, tense and voice.

Final cleanup of eventqueue doxy comments

Finish basic examples for all eventqueue methods

Add inline doxy examples for eventqueue method calls

Patch EventQueue doxygen to remove templatewall ...

In the doxygen only segment define generic function declarations for the docs

Finished initial rework, pending TODOs for param comments