fatal error C1060: compiler is out of heap space while compilimg sources

I am trying to compiling UE4 source code with visual studio2015 (upd2) . Win8 -64bit 10G Ram, total ram usage<70%.
What to do with this problem?

My guess is this isn’t actually a ram issue and is more likely a hard drive space issue. When compiling very large projects that use a large amount of ram, your PC might use a swap file to store some of the in-memory compilation, so the RAM is free for other more crucial things.

Maybe this link of suggested solutions can help you Fatal Error C1060 | Microsoft Docs

If you are using incredibuild you might want to update to the latest version which may also fix your issue.

just for fun https://twitter.com/Evl_Spirit/status/993777818294276096