Adjustign archs + compilers right before build

.github/workflows/wheels.yml

@@ -17,12 +17,11 @@ jobs:
         # https://github.com/github/feedback/discussions/7835#discussioncomment-1769026
         buildplat:
         # should also be able to do multi-archs on a single entry, e.g.
-        # [windows-2019, win*, "AMD64 x86"]. However, those two require a different compiler setup
-        # so easier to separate out here.
-        - [ubuntu-22.04, manylinux, x86_64]
-        - [ubuntu-22.04, musllinux, x86_64]
-        - [macos-11, macosx, x86_64]
-        - [windows-2019, AMD64]
+        # [os-image, os-name, os-arch]
+        - [ubuntu-latest, manylinux, x86_64]
+        - [ubuntu-latest, musllinux, x86_64]
+        - [macos-latest, macosx, x86_64]
+        - [windows-latest, win, AMD64] 
         # os: [windows-latest]
         # cibw_arch: ["AMD64"]
         # cibw_python: ["cp38-*", "cp39-*", "cp310-*", "cp311-*"]
@@ -45,16 +44,26 @@ jobs:
         run: |
           python -m pip install cibuildwheel
 
+      - name: Set compiler 
+        run: | 
+          if [ ${{ matrix.buildplat[1] }} == 'macosx' ]; then
+            echo "CC=/usr/local/opt/llvm/bin/clang" >> $GITHUB_ENV
+            echo "CXX=/usr/local/opt/llvm/bin/clang++" >> $GITHUB_ENV
+          elif [ ${{ matrix.buildplat[1] }} == 'win' ]; then
+            echo "CC=gcc" >> $GITHUB_ENV
+            echo "CXX=g++" >> $GITHUB_ENV
+          fi
+          $CXX --version
       - name: Build wheels
         uses: pypa/[email protected]
         env:
+          CIBW_BUILD: ${{ matrix.python[0] }}-${{ matrix.buildplat[1] }}*
+          CIBW_ARCHS: ${{ matrix.buildplat[2] }}
           # define CC, CXX so meson will use clang-cl instead of MSVC
           # CC: clang-cl
           # CXX: clang-cl
           # CC: gcc
           # CXX: g++
-          CIBW_BUILD: ${{ matrix.python[0] }}-${{ matrix.buildplat[1] }}*
-          CIBW_ARCHS: ${{ matrix.buildplat[2] }}
           # -Wl,-S equivalent to gcc's -Wl,--strip-debug
           # LDFLAGS: "-Wl,-S"
 

meson.build

@@ -36,15 +36,28 @@ _cpp_args = compiler.get_supported_arguments(
   '-Wno-conversion',
   '-Wno-misleading-indentation',
   '-Wno-unused-lambda-capture',
-  '-Wno-unused-parameter',
-  '-std=c++20', 
+  '-Wno-unused-parameter', 
   '-fPIC', 
   '-fvisibility=hidden',
   # '-flto=thin'        # release only: thin LTO 
   # '-flto'             # release only: monolithic LTO 
   '-Wno-deprecated-anon-enum-enum-conversion' # to silence Eigen 3.4 warnings
 )
 
+## Require C++20 for concepts
+concept_code = '''
+#include <concepts>
+#include <type_traits>
+template <class T>
+concept integral = std::is_integral_v<T>;
+'''
+concepts_check = compiler.compiles(concept_code, name : 'concepts check')
+if concepts_check
+  _cpp_args += compiler.get_supported_arguments('-std=c++20')
+else 
+  error('A C++20-compliant compiler is required')
+endif
+
 ## Add Xclang 
 _cpp_args += compiler.get_supported_arguments('-Xclang')