[ci] MacOS: Install GCC from homebrew

Author: rleh

.github/workflows/macos.yml

@@ -7,10 +7,6 @@ jobs:
     runs-on: macos-13
 
     steps:
-      # update Xcode version to fix linker bug
-      # - uses: maxim-lobanov/setup-xcode@v1
-      #   with:
-      #     xcode-version: '14.2'
 
       - name: Setup environment - Brew tap
         run: |
@@ -21,7 +17,8 @@ jobs:
         run: |
           export HOMEBREW_NO_INSTALL_CLEANUP=1 # saves time
           brew update
-          brew install doxygen boost gcc avr-gcc@12 arm-gcc-bin@12 cmake || true
+          brew unlink gcc
+          brew install doxygen boost gcc@12 avr-gcc@12 arm-gcc-bin@12 cmake || true
           brew link --force avr-gcc@12
           # brew upgrade boost gcc git || true
 
@@ -60,11 +57,6 @@ jobs:
         with:
           submodules: 'recursive'
 
-      - name: Update lbuild
-        if: always()
-        run: |
-          pip3 install --upgrade --user --upgrade-strategy=eager modm
-
       - name: Hosted Unittests
         if: always()
         run: |