Sync to ETL 20.27.2

Sync to 20.27.2

Sync to 20.24.1

20.24.1
callback and message timers now use etl::timer_semaphore_t instead of et::atomic_uint_least16_t
Fixed send_message function signatures.

20.24.0
#503 Algorithm transform uses expensive post increment operator - Fixed for all occurences of iterator increment.
#504 ETL_CONSTANT vs const in binary.h - Fixed.
Many algorithms will leverage built-ins, if available. Dependant on compiler version.
Added detection or selection of built-ins.
Much of etl::string and etl::string_view can be constexpr.
Added ETL initializer_list implementations that are compatible with major compilers.
Added etl::construct_at support.

Sync to ETL 20.23.0

20.23.0
Recoded state_chart to reduce its resource requirements.
Added compile time state chart variants.
Added etl::unaligned_type for fundamental types.
Added reverse engineered functionality from C++20 .
Added all permutations of leading/trailing bit tests.
Changed inline functions to templates in binary.h.
Added etl::midpoint and etl::lerp
Recoded etl::endian & etl::endianness to allow constexpr in certain configurations.
Updates and fixes to etl::bitset. Added to_ulong, to_ullong, to_string member functions.
Moved void_t definition.
Renamed 8bit check macro.
Updated tests to support C++20 STL.
Modified C++ language level detection.
Added all permutations of leading/trailing bit tests.
etl::iterator is more SFINAE compatible.
Updated C++ standard detection.

Sync to ETL 20.22.0

===============================================================================
20.22.0
Split callback and message timer to atomic and locked interrupt versions.
#480 Fixed: Double formatting with precision > 9
#481 Fixed: etl::span const datacannot be created from non const c array of data.
#482 Fixed: Two or more etl::span/array_view of different types create ambiguous overloading set
#483 Fixed: Added Green Hills compiler to minmax push and pop.
#484 Fixed: etl::vector test_uninitialized_resize_excess not calling uninitialized_resize.
#485 Fixed: etl::message_packet takes message types that are not in its list.

===============================================================================
20.21.0
Added contains() method to etl::map and etl::set + variants.
Added support for transparent comparators.
When ETL_NO_ATOMICS is defined the timer.h file does not define timer_semaphore_t.
etl::deque::resize throws etl::deque_full instead of etl::deque_out_of_bounds, if requested size is too large.

===============================================================================
20.20.0
Updated container 'insert' and 'erase' to C++11 style const_iterator parameters. (#463)
Fixed container template function overload abiguity. (#466)
Harmonize copy ctor and assignment for etl::delegate. (#465)
Added constexpr support for etl::enum_type. (#462)
Added 'make' functions to construct containers.
Remove unnecessary casts that causes warnings. (#461)
Added non-const string pointer overload. (#449)
Changed != to < in etl::ipool to get rid of erroneous clang-tidy nullptr dereference warning. (#457)
Added ifdef guard for MSVC pragma (#455)

===============================================================================
20.19.0
Updates to etl::delegate. Added more constexpr and set() functions.
Removed conanfile.py. Now controlled by conan repository.
Fixed missing 'typename' keyword in etl::multi_span.
Added missing explicit initialisation from in_place structures.
Fixed hidden parameter warning in unordered_map, unordered_multimap, unordered_set, unordered_multiset.
Disable etl::begin(), etl::end() and etl::size() for STL & >= C++11.
Add available_bytes to byte_stream_reader & byte_stream_writer.
Meson tests & style fix (#447).
Fix constexpr accepts() implementation to be C++11 compliant (#451, #452)
Fix-compiler-error-msvc-16 #454

===============================================================================
20.18.1
Added missing 'start, length' read() variants for byte_stream_reader.
Added multi_span to 'sanity checks'.

===============================================================================
20.18.0
Added front() access to locked queues.
Added .clang-format rules.
Added etl::pool_ext and etl::generic_pool_ext.
Added etl::multi_span.
Added CMSIS RTOS2 mutex variant.
Added 'unchecked' read and write membvers functions to byte_stream_reader and byte_stream_writer.
Fixed byte_stream_reader to be able to use const buffers.
Removed compiler warning messages.
Fixed missing 'public' access for message_router_registry iterator.

===============================================================================
20.17.3
Modified etl::cyclic_value for ARMCC v5 compatibility

===============================================================================
20.17.2
Replaced std::size_t with size_t in etl::in_place_index

===============================================================================
20.17.1
Added successor handling for accepts()
Added successor handling for pre-C++17 message router

===============================================================================
20.17.0
Added etl::result type
Added etl::byte_stream
Added denominated etl::to_string overloads
Added etl::remove_cvref to type traits
Replaced etl::remove_reference_t with etl::remove_cvref_t in variadic etl::variant
Added call_if and call_or member functions to etl::delegate
Improved compliance with MISRA rules
Extended 'successor' handling for all derived message router types

===============================================================================
20.16.2
Fixed incomplete template specialisations in type_traits.h for C++11

===============================================================================
20.16.1
Fix for etl::mutex::try_lock() for GCC

===============================================================================
20.16.0
Added C++17 variadic versions of etl::message_router and etl::fsm
'pop_into' in queue and stack will move if possible.
Added Force C++03 option to Github CI
Expanded compiled variants for scripts

===============================================================================
20.15.1
Fixed etl::fsm C++03 template definition that was corrupted in 20.10.0
Fixed meson.build

===============================================================================
20.15.0
Added a Bipartite buffer, by Benedek Kupper.
etl::bip_buffer_spsc_atomic
notify_observers() takes universal reference for C++11 and above.
Updated type traits generator.

===============================================================================
20.14.1
Changed std::forward to etl::forward in etl::variant (variadic)

===============================================================================
20.14.0
Added a vaiadic version of etl::variant. Usable for C++11 and up.
Added etl::overload pattern class. Groups lambdas into a functor class.
Refactored type_traits.h. Uses STL, compiler built-ins or user defined specialisations, dependent on settings.
Added etl::conditional_t to type_traits.h
Added etl::conjunction and etl::disjunction to type_traits.h
Added etl::integer_sequence to utility.h
Added etl::in_place, etl::in_place_t and etl::in_place_index_t.
Fixed missing etl::alignment_of specialisation for const void.

===============================================================================
20.13.0
Added a specialisation of etl::delegate_service to allow constexpr service.

===============================================================================
20.12.0
Added the option to derived etl::message<> from a parent class other than etl::imessage.
The parent class must ultimately be derived from etl::imessage.

===============================================================================
20.11.5
Added Arduino examples.

Sync to ETL 20.11.5

===============================================================================
20.11.5
Added Arduino examples.

Sync to ETL 20.11.4

===============================================================================
20.11.4
Fixed etl::circular_buffer copy and move assignment bug where the destination
buffer was not cleared before assignment.

===============================================================================
20.11.3
Define missing macro when cross compiling with clang for AVR

===============================================================================
20.11.2
etl::basic_string::copy is now const and does not affect truncation flags.

===============================================================================
20.11.1
Fixed ambiguous function call in etl::mem_cast for clang.

===============================================================================
20.11.0
Added etl::mem_cast, etl::mem_cast_ptr & etl::mem_cast_types for reinterpretion of memory blocks.
State tables in etl::debounce are now constexpr in C++11 or above.

===============================================================================
20.10.6
Updated QueuedMessageRouter and QueuedFSM examples to use current message frameworks.

===============================================================================
20.10.5
Added container_type to etl::stack, etl::queue and etl::priority_queue.

===============================================================================
20.10.4
Fixed cross compiler compatibility for etl::circular_buffer.

===============================================================================
20.10.3
Fixed etl::fsm generator for non-default number of message types.

===============================================================================
20.10.2
Fixed misspelled histogram class.

===============================================================================
20.10.1
Fixed incorrect histogram end() and cend() return values.

===============================================================================
20.10.0
Added Hierarchical Finite State Machine (etl::hfsm) derived from etl::fsm

===============================================================================
20.9.3
Fixed misspelt DBL_MAX macro.

===============================================================================
20.9.2
Fixed ETL_ASSERT for non-class types in etl::pool.

===============================================================================
20.9.1
Replaced std::distance with etl::distance in erase() and erase_if() for vector.h

===============================================================================
20.9.0
Fixed #362 'etl::fsm::receive() partial override'.
Fixed #363 'circular_buffer operator [] takes integer rather than size_type'.
Fixed occasional incorrect string length for etl::make_string.
Added macros for compilers that don't support HUGE_VAL.
Added etl::accumulate, etl::clamp, etl::erase, etl::erase_if, etl::remove, etl::remove_if.
Added maths algorithms and functors.
etl::correlation
etl::covariance
etl::gamma_encode
etl:;gamma_decode
etl::histogram
etl::sparce_histogram
etl::mean
etl::invert
etl::threshold
etl::quantize
etl::limiter
etl::rescale
etl::rms
etl::standard_deviation
etl::variance

===============================================================================
20.8.0
Added more CRCs, generalised table creation.
Options for table sizes of 4, 16 and 256.
Removed unnecessary non-const versions of iterators for containers.

===============================================================================
20.7.0
Added etl::selection_sort.
etl::delegate accepts moveable parameters.
Fixed the return type of const iterators for containers from const_iterator to iterator.
Changed many instances of 'static const' to 'static ETL_CONSTANT'.

===============================================================================
20.6.3
Updates to unit test CMake files.
Added missing include for string_utilities.h

===============================================================================
20.6.2
C++98/03 compatibility fixes.
Added 'sanity check' tests for checking for 98/03/11/14/17 issues.

===============================================================================
20.6.1
Added missing etl::atomic from gcc & clang implementations.
Changed nullptr to ETL_NULLPTR in buffer_descriptors and multi_range.
Fixed header includes in state_chart.h

===============================================================================
20.6.0
Added etl::message_router_registry.
Changed etl::flat_multimap & etl::flat_multiset to iterate in insertion order, as per C++11 map and set.
Added ETL_CONSTEXPR to etl::array.
C++98 compatibility fixes.
Remove unnecessary template keyword to destroy() call in etl::pool.
Abstracted unit test framework header.

===============================================================================
20.5.2
Fixed template aliases when using STL and below C++14

===============================================================================
20.5.1
Fixed ambiguous template error for etl::extent.

===============================================================================
20.5.0
Added specialisation of etl::state_chart to allow a parameter to be passed along
with the event.
Issue #339 - Fix extent type conversion warning
Issue #340 - Export headers as system includes

===============================================================================
20.4.1
Updates to etl::shared_message example application.

===============================================================================
20.4.0
Added uninitialized_resize() to etl::vector and etl::basic_string.

===============================================================================
20.3.1
Added ETL_CONSTANT to numeric_limits member functions.

===============================================================================
20.3.0
Added initialize_free_space(), trim_to_terminator() and data_end() functions to
strings for easier integration with C APIs.

===============================================================================
20.2.3
Fixed indexing error in find_next() for etl::bitset.

Sync to ETL 20.2.2

Added non-const get_message() member funtions in shared message framework.
Modified reference_counted_message_pool::allocate() return type.
Changed from etl::ireference_counted_message* to etl::reference_counted_message<TMessage, TCounter>*
Allow default constructed messages for shared messages.
Changed template aliases so they are available for C++11 rather than C++14.
Removed source 'etl::imessage_router&' parameter from the message framework 'receive'
and 'on_receive' member functions.
Added move constructor and move assignment operator to etl::shared_message.
Fixed rollover error for etl::queue_spsc_atomic
Added 'required_alignment' parameter to 'allocate' for etl::imemeory_block_allocator.
Updated QueuedMessageRouter example.
Exclude integral types from being considered for iterator range container constructors.
Added shared messages to the messaging framework + supporting allocator classes.
Some refactoring of the messaging framework internals.
Added example application for shared messages.
Added a lockable queue with locks implemented as pure virtuals.
Refeactored the other queues.
Fixed missing virtual destructor for C++11 observer.
Added etl::successor class for consistant 'chain of responsibilty' pattern generation.
Added missing constructors to unique_ptr.
Added nullptr check to unique_ptr destructor.
Fixed VS2019 warning for etl::deque iterators.
Added a virtual on_task_added callback to the scheduler.
Added a runtime multi range nested loop class.
Added etl::for_each.
Added is_random_access_iterator and deprecated is_random_iterator.
Added VS2019 Delegate function interrupt service example.
Added nullptr check to unique_ptr destructor.
Fixed VS2019 warning for etl::deque iterators.
Added constructors with deleters for unique_ptr.
Added virtual function 'void on_task_added()' that is called when a task is added to a scheduler.

Fixed LGT8F macro name clash

The LGT8F defined macros that clashed with ETL template parameter names.

Unknown board type is no longer an error

19.3.7

Unknown board is nor an error

Improved Arduino compatibility

19.3.6

Updated compatibility