Fix gcc installation on macOS CI runners

Author: rikyoz

.github/workflows/test_macos.yml

@@ -86,7 +86,7 @@ jobs:
     - uses: actions/checkout@v6
 
     - name: Install XCode
-      if: ${{ contains(matrix.os, 'macos-15') }}
+      if: ${{ contains(matrix.os, 'macos-15') || contains(matrix.os, 'macos-26') }}
       uses: maxim-lobanov/setup-xcode@v1
       with:
         xcode-version: latest-stable
@@ -109,6 +109,18 @@ jobs:
       run:
         brew reinstall gcc@14
 
+    - name: Reinstall GCC 14 on macOS 26
+      if: ${{ contains(matrix.os, 'macos-26') && contains(matrix.c_compiler, 'gcc-14') }}
+      shell: bash
+      run:
+        brew reinstall gcc@14
+
+    - name: Reinstall GCC 15 on macOS 26
+      if: ${{ contains(matrix.os, 'macos-26') && contains(matrix.c_compiler, 'gcc-15') }}
+      shell: bash
+      run:
+        brew reinstall gcc@15
+
     - name: Building and testing bit7z
       uses: ./.github/actions/ci_action
       with: