Add venv on Mac and do not use --user flag in that case

.github/workflows/build-python.yml

@@ -168,9 +168,17 @@ jobs:
         run: |
           bash .github/scripts/python.sh -d
 
+      - name: Create virtual on MacOS
+        if: runner.os == 'macOS'
+        run: |
+          python$PYTHON_VERSION -m venv venv
+          source venv/bin/activate
+          echo "PATH=$(pwd)/venv/bin:$PATH" >> $GITHUB_ENV
+          python -m pip install --upgrade pip
+
       - name: Install Python Dependencies
         shell: bash
-        run: python$PYTHON_VERSION -m pip install --break-system-packages --user -r python/dev_requirements.txt
+        run: python$PYTHON_VERSION -m pip install -r python/dev_requirements.txt
 
       - name: Build
         shell: bash

python/CMakeLists.txt

@@ -266,7 +266,7 @@ endif()
 # Add custom target so we can install with `make python-install`
 set(GTSAM_PYTHON_INSTALL_TARGET python-install)
 add_custom_target(${GTSAM_PYTHON_INSTALL_TARGET}
-        COMMAND ${PYTHON_EXECUTABLE} -m pip install --break-system-packages --user .
+        COMMAND ${PYTHON_EXECUTABLE} -m pip install $(if [ -z "$VIRTUAL_ENV" ]; then echo "--user"; fi) .
         DEPENDS ${GTSAM_PYTHON_DEPENDENCIES}
         WORKING_DIRECTORY ${GTSAM_PYTHON_BUILD_DIRECTORY})