title: Building UE4 from source - Mathcalls syntax errors
body: <p>I'm trying to build UE4 from source on my Debian (stretch) system.</p>
  
  <p>I've followed all of the instructions from <a href="https://docs.unrealengine.com/en-US/Platforms/Linux/BeginnerLinuxDeveloper/SettingUpAnUnrealWorkflow/index.html" rel="nofollow noreferrer">the official guide</a>, but running <code>make</code> gives some nasty errors from UE4's bundled mathcalls header.</p>
  
  <p>Here is my log:
  <a href="https://pastebin.com/4iMM7G4w" rel="nofollow noreferrer">https://pastebin.com/4iMM7G4w</a></p>
  
  <p>I've tried following the guide again from the start (including re-downloading the source), and I've (unsuccessfully) tried to update to clang-7; but I've just seen that clang is actually bundled with UE4, so that shouldn't be the problem.</p>
  
  <p>Thanks in advance, any help is very much appreciated.</p>
  
  <hr>
  
  <p>UPDATE: Compiling was able to continue when running with superuser privileges, <code>sudo make</code>.
  However, it looks like the makefile realizes it has root privileges and cancels the build because of it - see line 49 in this log: <a href="https://pastebin.com/rH34Fv06" rel="nofollow noreferrer">https://pastebin.com/rH34Fv06</a></p>