build with clang

Linux CI switches to clang 22; fixes what that exposed - export on
out-of-line member definitions, missing std includes, missing glm
imports. GCC 16 still builds.

.github/workflows/build_bin.yml

@@ -149,7 +149,7 @@ jobs:
           sudo apt-get update
 
           sudo apt-get install -y \
-            build-essential gcc-14 g++-14 ninja-build \
+            build-essential ninja-build wget lsb-release software-properties-common gnupg \
             libgl1-mesa-dev \
             libglew-dev \
             libglfw3-dev \
@@ -163,6 +163,15 @@ jobs:
             libwayland-dev \
             wayland-protocols
 
+      - name: Install LLVM/Clang 22
+        run: |
+          # Noble ships Clang 18, whose C++20 module support is not good enough
+          # for this tree; apt.llvm.org has current releases.
+          wget -qO /tmp/llvm.sh https://apt.llvm.org/llvm.sh
+          chmod +x /tmp/llvm.sh
+          sudo /tmp/llvm.sh 22
+          sudo apt-get install -y clang-tools-22   # clang-scan-deps, needed to scan modules
+
       #
       # Existing MaSzyna CI already builds OpenAL Soft 1.24.2,
       # so retain that instead of relying only on Ubuntu's package.
@@ -193,17 +202,16 @@ jobs:
 
       - name: Show environment
         run: |
-          gcc-14 --version
-          g++-14 --version
+          clang-22 --version
+          clang-scan-deps-22 --version
           ninja --version
           cmake --version
           python --version
 
       - name: Configure
         env:
-          # C++20 named modules need GCC 14+; noble's default build-essential is GCC 13
-          CC: gcc-14
-          CXX: g++-14
+          CC: clang-22
+          CXX: clang++-22
         run: |
           cmake \
             -S . \
@@ -215,7 +223,7 @@ jobs:
             -DWITH_OPENVR=OFF \
             -DUSE_LTO=OFF \
             -DPython3_EXECUTABLE="${{ steps.python.outputs.python-path }}" \
-            -DCMAKE_CXX_FLAGS="-Wno-attributes -fno-inline-functions-called-once"
+            -DCMAKE_CXX_FLAGS="-Wno-attributes"
 
       - name: Build
         run: |