ci/mac: remove unnecessary cc and ccx variables

Author: Akemi

.github/workflows/build.yml

@@ -227,10 +227,6 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        cc:
-          - "clang"
-        cxx:
-          - "clang++"
         os:
           - "macos-13"
           - "macos-14"
@@ -279,8 +275,6 @@ jobs:
         run: |
           ./ci/build-macos.sh
         env:
-          CC: "${{ matrix.cc }}"
-          CXX: "${{ matrix.cxx }}"
           TRAVIS_OS_NAME: "${{ matrix.os }}"
 
       - name: Create App Bundle