This issue has been closed as 'Won't Fix' due to an extended period of time without updates. If this issue is important to you please let us know by posting on the AnswerHub or UDN, and Epic will re-open the ticket for further review.
When building the source for the engine in Visual Studio 2015, if bDebugBuildsActuallyUseDebugCRT is set to true and the build configuration is Debug Editor, the build will fail.
Full output log from VS2015 upon failing to build source for 4.11 Preview 4 via Github.
1. Pull a source build of the engine and generate project files for Visual Studio 2015 (This will not occur when building with 2013)
2. Open BuildConfiguration.cs and then search for the following line:
bDebugBuildsActuallyUseDebugCRT = false;
3. On that line, replace "false" with "true"
4. Attempt to build the engine for the Debug Editor configuration
Result: The editor fails to build with multiple error messages
Expected: The editor should build without any issues
Head over to the existing Questions & Answers thread and let us know what's up.