[ci] set brew gcc-ar and ranlib with full path

.github/workflows/build_all.yml

@@ -47,8 +47,6 @@ jobs:
           conda install octave
           brew link --force libomp
           brew install --cask lazarus
-          which gcc-ar-12
-          which gcc-ranlib-12
           echo "/Applications/Lazarus/" >> $GITHUB_PATH
       - name: Install dependencies (Windows only)
         if: ${{ runner.os == 'Windows' }}
@@ -158,7 +156,7 @@ jobs:
             make AR=g++ BACKEND=cudastatic USERLINKOPT='lib/libzmat.a -Wl,-Bstatic -lgomp -Wl,-Bdynamic'
             ldd ../bin/mcx
           elif [[ "$RUNNER_OS" == "macOS" ]]; then
-            mkdir build && cd build && cmake .. -DCMAKE_AR="gcc-ar-12" -DCMAKE_RANLIB="gcc-ranlib-12" && cat  && make VERBOSE=1 && cd ..
+            mkdir build && cd build && cmake .. -DCMAKE_AR="/usr/local/bin/gcc-ar-12" -DCMAKE_RANLIB="/usr/local/bin/gcc-ranlib-12" && cat  && make VERBOSE=1 && cd ..
             otool -L ../bin/mcx
             otool -L ../mcxlab/mcx.mex*
           else