diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 924fb2c..6ead611 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -24,13 +24,20 @@ jobs:
         os:
           - windows-latest
           - macOS-latest
-          - ubuntu-22.04
         config:
           - Release
+        include:
+          - os: ubuntu-22.04
+            config: Release
+            build_with_prebuilt_clang: 0
+          - os: ubuntu-22.04
+            config: Release
+            build_with_prebuilt_clang: 1
     runs-on: ${{ matrix.os }}
     env:
       OS: ${{ matrix.os }}
       CONFIG: ${{ matrix.config }}
+      BUILD_WITH_PREBUILT_CLANG: ${{ matrix.build_with_prebuilt_clang }}
       GH_TOKEN: ${{ secrets.GH_TOKEN }}
     steps:
 
diff --git a/build.sh b/build.sh
index da7d554..e014493 100755
--- a/build.sh
+++ b/build.sh
@@ -37,13 +37,16 @@ case "$(uname)" in
   sudo rm -rf /usr/share/dotnet /usr/local/lib/android /opt/ghc
   df -h
 
-  mkdir -p "${HOME}/clang+llvm"
-  pushd "${HOME}/clang+llvm"
-    # Install pre-built clang.
-    curl -fsSL -o clang+llvm.zip "https://github.com/mc-imperial/build-clang/releases/download/bootstrap-llvmorg-14.0.6/build-clang-llvmorg-14.0.6-${BUILD_PLATFORM}_Release.zip"
-    unzip clang+llvm.zip
-  popd
-  export PATH="${HOME}/clang+llvm/bin:$PATH"
+  if [ "${BUILD_WITH_PREBUILT_CLANG}" == 1 ]
+  then
+    mkdir -p "${HOME}/clang+llvm"
+    pushd "${HOME}/clang+llvm"
+      # Install pre-built clang.
+      curl -fsSL -o clang+llvm.zip "https://github.com/mc-imperial/build-clang/releases/download/bootstrap-llvmorg-14.0.6/build-clang-llvmorg-14.0.6-${BUILD_PLATFORM}_Release.zip"
+      unzip clang+llvm.zip
+    popd
+    export PATH="${HOME}/clang+llvm/bin:$PATH"
+  fi
   export CC=clang
   export CXX=clang++
   which "${CC}"
@@ -96,7 +99,18 @@ BUILD_DIR="b_${CONFIG}"
 mkdir "${BUILD_DIR}"
 
 case "$(uname)" in
-"Linux"|"Darwin")
+"Linux")
+  if [ "${BUILD_WITH_PREBUILT_CLANG}" == 0 ]
+  then
+    INSTALL_DIR="${INSTALL_DIR}-stock-clang"
+    cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX="${INSTALL_DIR}" -S llvm -B "${BUILD_DIR}" -DLLVM_ENABLE_PROJECTS="clang"
+  else
+    INSTALL_DIR="${INSTALL_DIR}-prebuilt-clang"
+    cmake -G Ninja -C clang/cmake/caches/Fuchsia.cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_INSTALL_PREFIX="${INSTALL_DIR}" -S llvm -B "${BUILD_DIR}"
+  fi
+  ;;
+
+"Darwin")
   cmake -G Ninja -C clang/cmake/caches/Fuchsia.cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DCMAKE_INSTALL_PREFIX="${INSTALL_DIR}" -S llvm -B "${BUILD_DIR}"
   ;;