Fix: try find protobuf config and get userver_protobuf_import_dir from libprotobuf target, otherwise find default protobuf

Author: RayeS2070

cmake/SetupProtobuf.cmake

@@ -41,7 +41,10 @@ if(NOT USERVER_FORCE_DOWNLOAD_PROTOBUF)
     if(USERVER_DOWNLOAD_PACKAGE_PROTOBUF)
         find_package(Protobuf QUIET)
     else()
-        find_package(Protobuf)
+        find_package(Protobuf CONFIG)
+        if (NOT Protobuf_FOUND)
+            find_package(Protobuf)
+        endif()
         if(NOT Protobuf_FOUND)
             message(
                 FATAL_ERROR

cmake/UserverGrpcTargets.cmake

@@ -52,7 +52,13 @@ function(_userver_prepare_grpc)
     elseif(protobuf_INCLUDE_DIRS)
         set_property(GLOBAL PROPERTY userver_protobuf_import_dir "${protobuf_INCLUDE_DIRS}")
     else()
-        message(FATAL_ERROR "Invalid Protobuf package")
+        # maybe we found protobuf config
+        get_target_property(_incs protobuf::libprotobuf INTERFACE_INCLUDE_DIRECTORIES)
+        if (_incs)
+            set_property(GLOBAL PROPERTY userver_protobuf_import_dir "${_incs}")
+        else()
+            message(FATAL_ERROR "Invalid Protobuf package")
+        endif()
     endif()
 
     if(NOT Protobuf_VERSION)
@@ -61,7 +67,7 @@ function(_userver_prepare_grpc)
     if(NOT gRPC_VERSION)
         message(FATAL_ERROR "Invalid gRPC package")
     endif()
-    if(NOT PROTOBUF_PROTOC)
+    if(NOT PROTOBUF_PROTOC AND NOT TARGET protobuf::libprotoc)
         message(FATAL_ERROR "protoc not found")
     endif()
     if(NOT PROTO_GRPC_CPP_PLUGIN)