Fix rpath for libomp dylib at wheel repair

.github/workflows/publish_pypi.yml

@@ -139,7 +139,9 @@ jobs:
         env:
           CIBW_BEFORE_BUILD_MACOS: >
             python -m pip install --upgrade cmake casadi setuptools wheel
-          CIBW_REPAIR_WHEEL_COMMAND_MACOS: delocate-listdeps {wheel} && delocate-wheel -v -w {dest_dir} {wheel}
+          CIBW_REPAIR_WHEEL_COMMAND_MACOS: |
+            python scripts/fix_macos_wheel.py
+            delocate-listdeps {wheel} && delocate-wheel -v -w {dest_dir} {wheel}
           CIBW_TEST_COMMAND: python -c "import pybamm; pybamm.IDAKLUSolver()"
 
       - name: Upload wheels for ${{ matrix.os }}
@@ -173,7 +175,9 @@ jobs:
         run: python -m pipx run cibuildwheel --output-dir wheelhouse
         env:
           CIBW_BEFORE_BUILD: python -m pip install cmake casadi setuptools wheel delocate
-          CIBW_REPAIR_WHEEL_COMMAND: delocate-listdeps {wheel} && delocate-wheel -v -w {dest_dir} {wheel}
+          CIBW_REPAIR_WHEEL_COMMAND_MACOS: |
+            python scripts/fix_libomp_rpath_macos.py
+            delocate-listdeps {wheel} && delocate-wheel -v -w {dest_dir} {wheel}
           CIBW_TEST_COMMAND: python -c "import pybamm; pybamm.IDAKLUSolver()"
 
       - name: Upload wheels for macOS arm64

scripts/fix_libomp_rpath_macos.py

@@ -0,0 +1,19 @@
+# A helper script to fix the rpath of the OpenMP dynamic library. This
+# is to be used when building the wheels for PyBaMM on macOS (on both
+# amd64 and arm64 architectures).
+
+import os
+import subprocess
+
+homedir = os.path.expanduser("~")
+libomp_path = os.path.join(homedir, ".local/lib/libomp.dylib")
+
+subprocess.run(
+    [
+        "install_name_tool",
+        "-change",
+        "/usr/local/lib/libomp.dylib",
+        libomp_path,
+        libomp_path,
+    ]
+)