ci: test installed packages using CMake

.github/workflows/psp.yaml

@@ -13,6 +13,24 @@ jobs:
         apk update 
         apk add cmake gmp mpc1 mpfr4 make
     - name: Configure CMake
-      run: cmake -S. -Bbuild -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=$PSPDEV/psp/share/pspdev.cmake -DSDL_TEST=ON
+      run: |
+        cmake -S . -B build \
+          -DCMAKE_TOOLCHAIN_FILE=$PSPDEV/psp/share/pspdev.cmake \
+          -DSDL_TESTS=ON \
+          -DCMAKE_BUILD_TYPE=Release \
+          -DCMAKE_INSTALL_PREFIX=prefix
     - name: Build
-      run: cmake --build build
+      run: cmake --build build --config Release
+    - name: Install
+      run: |
+        echo "SDL2_DIR=$(pwd)/prefix" >> $GITHUB_ENV
+        cmake --install build --config Release
+        ( cd prefix; find ) | LC_ALL=C sort -u
+    - name: Verify CMake configuration files
+      run: |
+        cmake -S cmake/test -B cmake_config_build \
+          -DCMAKE_TOOLCHAIN_FILE=$PSPDEV/psp/share/pspdev.cmake \
+          -DCMAKE_PREFIX_PATH=${{ env.SDL2_DIR }} \
+          -DTEST_SHARED=FALSE \
+          -DCMAKE_BUILD_TYPE=Release
+        cmake --build cmake_config_build --verbose