MSBuild has the ability to output multiple logs with different filters. To make our logging more useful for quick review, I dialed the logging level back to errors only. However, we should also include warnings. Unfortunately, there is no built-in "errors and warnings" logging level. Instead, lets log errors to one log file, warnings to another, and concatenate them (errors first) when our existing AssembleBuildLogs command runs at the end of the build.
Created attachment 248021 [details] Patch
Committed r181125: <http://trac.webkit.org/changeset/181125>