cmake: only install channelz if gRPC_USE_PROTO_LITE is off (#25772)

* only install channelz if not USE_PROTO_LITE

* adapted CMakeLists.txt.template to not install channelz when USE_PROTO_LITE

CMakeLists.txt

@@ -3800,7 +3800,9 @@ endif()
 
 if(gRPC_BUILD_CODEGEN)
 
-if(gRPC_INSTALL)
+# grpcpp_channelz doesn't build with protobuf-lite, so no install required
+# See https://github.com/grpc/grpc/issues/22826
+if(gRPC_INSTALL AND NOT gRPC_USE_PROTO_LITE)
   install(TARGETS grpcpp_channelz EXPORT gRPCTargets
     RUNTIME DESTINATION ${gRPC_INSTALL_BINDIR}
     LIBRARY DESTINATION ${gRPC_INSTALL_LIBDIR}

templates/CMakeLists.txt.template

@@ -685,7 +685,13 @@
   </%def>
 
   <%def name="cc_install(tgt)">
+  % if tgt.name == 'grpcpp_channelz':
+  # grpcpp_channelz doesn't build with protobuf-lite, so no install required
+  # See https://github.com/grpc/grpc/issues/22826
+  if(gRPC_INSTALL AND NOT gRPC_USE_PROTO_LITE)
+  % else:
   if(gRPC_INSTALL)
+  % endif
     install(TARGETS ${tgt.name} EXPORT gRPCTargets
       RUNTIME DESTINATION <%text>${gRPC_INSTALL_BINDIR}</%text>
       LIBRARY DESTINATION <%text>${gRPC_INSTALL_LIBDIR}</%text>