Only install howardhinnant_date on macOS

Signed-off-by: Julien Jerphanion <git@jjerphan.xyz>

Co-authored-by: Johan Mabille <johan.mabille@gmail.com>

.github/workflows/osx.yml

@@ -37,6 +37,14 @@ jobs:
  run: |
  echo " - clangxx==17.0.6" >> environment-dev.yml
 
+ - name: Add `howardhinnant_date` in the conda environment specification
+ run: |
+ # P0355R7 (Extending chrono to Calendars and Time Zones) has not been entirely implemented in libc++ yet.
+ # See: https://libcxx.llvm.org/Status/Cxx20.html#note-p0355
+ # For now, we use HowardHinnant/date as a replacement if we are compiling with libc++.
+ # TODO: remove this once libc++ has full support for P0355R7.
+ echo " - howardhinnant_date" >> environment-dev.yml
+
  - name: Set conda environment
  uses: mamba-org/setup-micromamba@main
  with:

environment-dev.yml

@@ -5,7 +5,5 @@ dependencies:
  # Build
  - cmake
  - ninja
- # Alternative of `std::chrono` introduced in C++20.
- - howardhinnant_date
  # Tests
  - doctest