Fix build error with clang

[luca-della-vedova]

When users try to include the realtime_box_best_effort.h header and build their project with clang the following error will come up (tested on Ubuntu 24.04 and Jazzy):

--- stderr: realtime_tools                              
In file included from /usr/local/google/home/lucadv/ws_control/src/realtime_tools/test/realtime_box_best_effort_tests.cpp:32:
/usr/local/google/home/lucadv/ws_control/src/realtime_tools/include/realtime_tools/realtime_box_best_effort.h:74:54: error: use of class template 'std::initializer_list' requires template arguments
   74 |     std::enable_if_t<std::is_constructible_v<U, std::initializer_list>>)
      |                                                      ^
/usr/bin/../lib/gcc/x86_64-linux-gnu/13/../../../../include/c++/13/initializer_list:45:11: note: template is declared here
   44 |   template<class _E>
      |   ~~~~~~~~~~~~~~~~~~
   45 |     class initializer_list
      |           ^
1 error generated.

I just added the template argument to the initializer list and this seems to satisfy clang / not break gcc.

Test it!

Just build with the clang mixin before and after this PR:

colcon build --mixin clang

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 75.51%. Comparing base (974c89c) to head (14ce701).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #183   +/-   ##
=======================================
  Coverage   75.51%   75.51%           
=======================================
  Files           8        8           
  Lines         343      343           
  Branches       54       54           
=======================================
  Hits          259      259           
  Misses         50       50           
  Partials       34       34           

Flag	Coverage Δ
unittests	75.51% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
include/realtime_tools/realtime_box_best_effort.h	87.87% <ø> (ø)

[saikishor]

LGTM

[christophfroehlich]

I saw the same warning, thx for fixing this!