Add cmake option protobuf_INSTALL for installation files (#7123)

cmake/CMakeLists.txt

@@ -41,6 +41,7 @@ if (CMAKE_CXX_COMPILER_ID MATCHES Intel)
 endif()
 
 # Options
+option(protobuf_INSTALL "Install protobuf binaries and files" ON)
 if(WITH_PROTOC)
   set(protobuf_PROTOC_EXE ${WITH_PROTOC} CACHE FILEPATH "Protocol Buffer Compiler executable" FORCE)
 endif()
@@ -305,7 +306,9 @@ if (protobuf_BUILD_CONFORMANCE)
   include(conformance.cmake)
 endif (protobuf_BUILD_CONFORMANCE)
 
-include(install.cmake)
+if (protobuf_INSTALL)
+  include(install.cmake)
+endif (protobuf_INSTALL)
 
 if (protobuf_BUILD_EXAMPLES)
   include(examples.cmake)