Only install anything if LIBZIP_DO_INSTALL is ON.

Closes #458.

CMakeLists.txt

@@ -477,19 +477,19 @@ include(CMakePackageConfigHelpers)
 write_basic_package_version_file("${PROJECT_BINARY_DIR}/${PROJECT_NAME}-config-version.cmake"
   COMPATIBILITY AnyNewerVersion)
 
-configure_package_config_file("${PROJECT_NAME}-config.cmake.in" "${PROJECT_BINARY_DIR}/${PROJECT_NAME}-config.cmake"
-  INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/libzip)
+if(LIBZIP_DO_INSTALL)
+  configure_package_config_file("${PROJECT_NAME}-config.cmake.in" "${PROJECT_BINARY_DIR}/${PROJECT_NAME}-config.cmake"
+    INSTALL_DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/libzip)
 
-# Install Find* modules, they are required by libzip-config.cmake to resolve dependencies
-install(FILES
+  # Install Find* modules, they are required by libzip-config.cmake to resolve dependencies
+  install(FILES
     ${CMAKE_CURRENT_SOURCE_DIR}/cmake/FindNettle.cmake
     ${CMAKE_CURRENT_SOURCE_DIR}/cmake/Findzstd.cmake
     ${CMAKE_CURRENT_SOURCE_DIR}/cmake/FindMbedTLS.cmake
-  DESTINATION
+    DESTINATION
     ${CMAKE_INSTALL_LIBDIR}/cmake/libzip/modules
-  )  
+  )
 
-if(LIBZIP_DO_INSTALL)
   # Add targets to the build-tree export set
   export(TARGETS zip
     FILE "${PROJECT_BINARY_DIR}/${PROJECT_NAME}-targets.cmake")