GHA: Update for homebrew changes on OSX

Author: Flamefire

.github/workflows/unit-tests.yml

@@ -162,13 +162,14 @@ jobs:
       - name: Install system packages
         run: |
           if [[ "${{runner.os}}" =~ macOS ]]; then
-            brew install cmake boost sdl2 sdl2_mixer gettext miniupnpc libiconv lua
-            echo /usr/local/opt/gettext/bin >> $GITHUB_PATH
-            echo "Available Boost installs: $(ls /usr/local/Cellar/boost/)"
+            echo "HOMEBREW_PREFIX=$HOMEBREW_PREFIX"
+            echo "HOMEBREW_CELLAR=$HOMEBREW_CELLAR"
+            brew install cmake boost sdl2 sdl2_mixer gettext miniupnpc lua
+            echo "Available Boost installs: $(ls "$HOMEBREW_CELLAR/boost/")"
             # Use the latest (last folder)
-            BOOST_ROOT=$(find /usr/local/Cellar/boost/* -maxdepth 0 -type d | tail -n1)
-            [[ -n "$BOOST_ROOT" ]]
+            BOOST_ROOT=$(find "$HOMEBREW_CELLAR/boost/"* -maxdepth 0 -type d | tail -n1)
             echo "Choosen Boost: $BOOST_ROOT"
+            [[ -n "$BOOST_ROOT" ]] || exit 1
             echo "BOOST_ROOT=${BOOST_ROOT}" >> $GITHUB_ENV
           else
             compiler=${{matrix.compiler}}