fix ONNX Runtime install layout so CMake can find it

The release tarball ships its CMake package files under lib/, but
onnxruntimeTargets.cmake resolves the library as <prefix>/lib64. Ubuntu
is multiarch, so CMake does not search lib64 for packages and ld.so does
not search /usr/local/lib64 at all, leaving find_package(onnxruntime)
failing on a stock install. Keep the libraries in lib64, move only the
package files to lib/cmake, and add lib64 to the linker path.

scripts/install_linux_x64.sh

@@ -35,7 +35,7 @@ else
 fi
 
 # --- ONNX Runtime (C++ GPU, installs to /usr/local) ---
-if [ -f /usr/local/lib64/libonnxruntime.so ] && [ -d /usr/local/include/onnxruntime ]; then
+if [ -f /usr/local/lib64/libonnxruntime.so ] && [ -d /usr/local/lib/cmake/onnxruntime ]; then
     echo ">>> ONNX Runtime already installed — skipping."
 else
     echo ">>> Downloading ONNX Runtime ${ORT_VERSION} GPU..."
@@ -49,6 +49,15 @@ else
     sudo cp -r "${TMP_DIR}/onnxruntime-linux-x64-gpu-${ORT_VERSION}/include/"* /usr/local/include/onnxruntime/
     sudo mkdir -p /usr/local/lib64
     sudo cp -r "${TMP_DIR}/onnxruntime-linux-x64-gpu-${ORT_VERSION}/lib/"* /usr/local/lib64/
+    # onnxruntimeTargets.cmake resolves the library as <prefix>/lib64, but Ubuntu
+    # is multiarch: CMake does not search lib64 for packages and ld.so does not
+    # search /usr/local/lib64 at all. Move only the package files to lib/cmake
+    # and put lib64 on the linker path.
+    sudo mkdir -p /usr/local/lib/cmake
+    sudo rm -rf /usr/local/lib/cmake/onnxruntime
+    sudo mv /usr/local/lib64/cmake/onnxruntime /usr/local/lib/cmake/
+    sudo rmdir /usr/local/lib64/cmake
+    echo /usr/local/lib64 | sudo tee /etc/ld.so.conf.d/onnxruntime.conf > /dev/null
     sudo ldconfig
 fi