Print real-time messages and warnings to console_log_file

Warnings and messages are still printed to
the console in bulk after each target is completed.
Fixes #588.

R/handlers.R

@@ -3,18 +3,17 @@ handle_build_exceptions <- function(target, meta, config) {
     warn_opt <- max(1, getOption("warn"))
     withr::with_options(
       new = list(warn = warn_opt),
-      drake_warning(
+      warning(
         "target ", target, " warnings:\n",
         multiline_message(meta$warnings),
-        config = config
+        call. = FALSE
       )
     )
   }
   if (length(meta$messages) && config$verbose) {
-    drake_message(
+    message(
       "Target ", target, " messages:\n",
-      multiline_message(meta$messages),
-      config = config
+      multiline_message(meta$messages)
     )
   }
   if (inherits(meta$error, "error")) {

R/run.R

@@ -23,10 +23,12 @@ with_handling <- function(target, meta, config) {
       withCallingHandlers(
         value <- with_call_stack(target = target, config = config),
         warning = function(w) {
+          drake_log_warning(w$message, config = config)
           warnings <<- c(warnings, w$message)
         },
         message = function(m) {
           msg <- gsub(pattern = "\n$", replacement = "", x = m$message)
+          drake_log_message(msg, config = config)
           messages <<- c(messages, msg)
         }
       ),