Add Xetra compilation

Author: martinfantini

.github/workflows/main.yml

@@ -16,7 +16,7 @@ jobs:
         run: curl -L https://archives.boost.io/release/1.72.0/source/boost_1_72_0.tar.gz | tar zx
         shell: bash
       - name: configure
-        run: cmake -Bbuild -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=ON
+        run: cmake -Bbuild -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=ON -DXETRA_FAST_SPECIFICATION=ON
       - name: build
         run: cmake --build build --parallel 2
       - name: test