fix build

.github/workflows/book.yml

@@ -17,9 +17,21 @@ jobs:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
-      - uses: ruby/setup-ruby@v1
-        with:
-          ruby-version: '3.4'
+      - name: Install Ruby
+        env:
+          CC: clang
+        run: |
+          url="https://cache.ruby-lang.org/pub/ruby/3.4/ruby-3.4.4.tar.gz"
+          prefix=`pwd`/rubies/ruby-3.4
+          mkdir rubies
+          mkdir ruby_src
+          curl -sSL $url | tar -xz
+          cd ruby-3.4.4
+          mkdir build
+          cd build
+          ../configure --without-shared --prefix=$prefix
+          make install
+          echo $prefix/bin >> $GITHUB_PATH
       - name: Install latest mdbook
         run: |
           tag=$(curl 'https://api.github.com/repos/rust-lang/mdbook/releases/latest' | jq -r '.tag_name')