Assertion failed on first run on Linux

After downloading and building the Engine following the 'Building on Linux" instructions, attempting to run the UE4Editor gives me the following error:

Using binned.
    Increasing per-process limit of core file size to infinity.
    [2015.12.09-10.29.55:783][  0]LogInit:Display: Running engine without a game
    [2015.12.09-10.29.55:783][  0]LogPlatformFile: Not using cached read wrapper
    [2015.12.09-10.29.55:783][  0]LogInit:Display: RandInit(101641034) SRandInit(101641040).
    [2015.12.09-10.29.55:783][  0]LogTaskGraph: Started task graph with 4 named threads and 7 total threads.
    [2015.12.09-10.29.55:783][  0]LogStats: Stats thread started at 1.216047
    [2015.12.09-10.29.55:783][  0]LogInit: Version: 4.10.0-0+++depot+UE4-Releases+4.10
    [2015.12.09-10.29.55:783][  0]LogInit: API Version: 0
    [2015.12.09-10.29.55:783][  0]LogInit: Compiled (64-bit): Dec  9 2015 12:01:25
    [2015.12.09-10.29.55:783][  0]LogInit: Compiled with Clang: 3.5.0 (tags/RELEASE_350/final)
    [2015.12.09-10.29.55:783][  0]LogInit: Build Configuration: Development
    [2015.12.09-10.29.55:784][  0]LogInit: Branch Name: ++depot+UE4-Releases+4.10
    [2015.12.09-10.29.55:784][  0]LogInit: Command line: 
    [2015.12.09-10.29.55:784][  0]LogInit: Base directory: /home/ioannis/VRSoftware/UnrealEngine/Engine/Binaries/Linux/
    [2015.12.09-10.29.55:784][  0]LogInit: Rocket: 0
    [2015.12.09-10.29.55:808][  0]LogInit: Using libcurl 7.38.0
    [2015.12.09-10.29.55:808][  0]LogInit:  - built for x86_64-unknown-linux-gnu
    [2015.12.09-10.29.55:808][  0]LogInit:  - supports SSL with OpenSSL/1.0.1i
    [2015.12.09-10.29.55:808][  0]LogInit:  - supports HTTP deflate (compression) using libz 1.2.5
    [2015.12.09-10.29.55:808][  0]LogInit:  - other features:
    [2015.12.09-10.29.55:808][  0]LogInit:      CURL_VERSION_SSL
    [2015.12.09-10.29.55:808][  0]LogInit:      CURL_VERSION_LIBZ
    [2015.12.09-10.29.55:808][  0]LogInit:      CURL_VERSION_IPV6
    [2015.12.09-10.29.55:808][  0]LogInit:      CURL_VERSION_ASYNCHDNS
    [2015.12.09-10.29.55:808][  0]LogInit:      CURL_VERSION_LARGEFILE
    [2015.12.09-10.29.55:808][  0]LogInit:      CURL_VERSION_TLSAUTH_SRP
    [2015.12.09-10.29.55:812][  0]LogInit:  Libcurl: checking if '/etc/pki/tls/certs/ca-bundle.crt' exists
    [2015.12.09-10.29.55:834][  0]LogInit:  Libcurl: checking if '/etc/ssl/certs/ca-certificates.crt' exists
    [2015.12.09-10.29.55:847][  0]LogInit:  CurlRequestOptions (configurable via config and command line):
    [2015.12.09-10.29.55:847][  0]LogInit:  - bVerifyPeer = true  - Libcurl will verify peer certificate
    [2015.12.09-10.29.55:848][  0]LogInit:  - bUseHttpProxy = false  - Libcurl will NOT use HTTP proxy
    [2015.12.09-10.29.55:848][  0]LogInit:  - bDontReuseConnections = false  - Libcurl will reuse connections
    [2015.12.09-10.29.55:848][  0]LogInit:  - CertBundlePath = /etc/ssl/certs/ca-certificates.crt  - Libcurl will set CURLOPT_CAINFO to it
    [2015.12.09-10.29.56:194][  0]LogInit: Presizing for 0 objects not considered by GC, pre-allocating 0 bytes.
    [2015.12.09-10.29.56:218][  0]LogInit: Object subsystem initialized
    [2015.12.09-10.29.56:252][  0]LogInit: Initializing SDL.
    Xlib:  extension "RANDR" missing on display ":0".
    [2015.12.09-10.29.56:522][  0]LogInit:Warning: Could not initialize SDL: XRandR support is required but not available                                                         
    [2015.12.09-10.29.56:523][  0]LogInit:Warning: FDisplayMetrics::GetDisplayMetrics: PlatformInitMultimedia() failed, cannot get display metrics                                
    [2015.12.09-10.29.56:591][  0]LogLinux: Selected Device Profile: [Linux]
    [2015.12.09-10.29.56:591][  0]LogInit: Applying CVar settings loaded from the selected device profile: [Linux]
    [2015.12.09-10.29.56:690][  0]LogInit: Linux hardware info:
    [2015.12.09-10.29.56:690][  0]LogInit:  - this process' id (pid) is 6568, parent process' id (ppid) is 2371
    [2015.12.09-10.29.56:690][  0]LogInit:  - we are not running under debugger
    [2015.12.09-10.29.56:690][  0]LogInit:  - machine network name is 'caveman'
    [2015.12.09-10.29.56:690][  0]LogInit:  - we're logged in locally
    [2015.12.09-10.29.56:690][  0]LogInit:  - Number of physical cores available for the process: 4
    [2015.12.09-10.29.56:690][  0]LogInit:  - Number of logical cores available for the process: 4
    [2015.12.09-10.29.56:690][  0]LogInit:  - Cache line size: 64
    [2015.12.09-10.29.56:690][  0]LogInit:  - Memory allocator used: binned
    [2015.12.09-10.29.56:690][  0]LogInit: Linux-specific commandline switches:
    [2015.12.09-10.29.56:690][  0]LogInit:  -nodwarf (currently OFF): suppress parsing of DWARF debug info (callstacks will be generated faster, but won't have line numbers)
    [2015.12.09-10.29.56:690][  0]LogInit:  -ansimalloc - use malloc()/free() from libc (useful for tools like valgrind and electric fence)
    [2015.12.09-10.29.56:690][  0]LogInit:  -jemalloc - use jemalloc for all memory allocation
    [2015.12.09-10.29.56:690][  0]LogInit:  -binnedmalloc - use binned malloc  for all memory allocation
    [2015.12.09-10.29.56:690][  0]LogInit:  -httpproxy=ADDRESS:PORT - redirects HTTP requests to a proxy (only supported if compiled with libcurl)
    [2015.12.09-10.29.56:690][  0]LogInit:  -reuseconn - allow libcurl to reuse HTTP connections (only matters if compiled with libcurl)
    [2015.12.09-10.29.56:690][  0]LogInit:  -virtmemkb=NUMBER - sets process virtual memory (address space) limit (overrides VirtualMemoryLimitInKB value from .ini)
    [2015.12.09-10.29.56:690][  0]LogInit: Setting LC_NUMERIC to en_US
    [2015.12.09-10.29.56:691][  0]LogInit: Initializing SDL.
    Xlib:  extension "RANDR" missing on display ":0".
    [2015.12.09-10.29.56:764][  0]LogInit:Warning: Could not initialize SDL: XRandR support is required but not available                                                         
    [2015.12.09-10.29.56:764][  0]LogInit:  - Physical RAM available (not considering process quota): 8 GB (7986 MB, 8178404 KB, 8374685696 bytes)
    [2015.12.09-10.29.56:950][  0]LogTextLocalizationManager: No specific translations for ('en-US') exist, so ('en') translations will be used.
    [2015.12.09-10.29.57:458][  0]LogInit: Initializing SDL.
    Xlib:  extension "RANDR" missing on display ":0".
    [2015.12.09-10.29.57:511][  0]LogInit:Warning: Could not initialize SDL: XRandR support is required but not available                                                         
    [2015.12.09-10.29.57:511][  0]LogInit:Warning: LinuxSplash_InitSplashResources() : PlatformInitMultimedia() failed, there will be no splash.                                  
    [2015.12.09-10.29.57:511][  0]LogInit: Initializing SDL.
    Xlib:  extension "RANDR" missing on display ":0".
    [2015.12.09-10.29.57:560][  0]LogInit:Warning: Could not initialize SDL: XRandR support is required but not available                                                         
    Fatal error: [File:/home/ioannis/VRSoftware/UnrealEngine/Engine/Source/Runtime/Core/Private/Linux/LinuxApplication.cpp] [Line: 36]                                            
    FLinuxApplication::CreateLinuxApplication() : PlatformInitMultimedia() failed, cannot create application instance.                                                            
    [2015.12.09-10.29.57:560][  0]LogLinux:Error: appError called: Assertion failed: Assertion failed:  [File:/home/ioannis/VRSoftware/UnrealEngine/Engine/Source/Runtime/Core/Private/Linux/LinuxApplication.cpp] [Line: 36]                                            
    FLinuxApplication::CreateLinuxApplication() : PlatformInitMultimedia() failed, cannot create application instance.                                                            
    
    Signal 11 caught.                                                                      
    EngineCrashHandler: Signal=11
    [2015.12.09-10.29.57:663][  0]LogLinux: === Critical error: ===
    Unhandled Exception: SIGSEGV: invalid attempt to access memory at address 0x00000003
    
    [2015.12.09-10.29.57:663][  0]LogLinux: Assertion failed: Assertion failed:  [File:/home/ioannis/VRSoftware/UnrealEngine/Engine/Source/Runtime/Core/Private/Linux/LinuxApplication.cpp] [Line: 36] 
    FLinuxApplication::CreateLinuxApplication() : PlatformInitMultimedia() failed, cannot create application instance.
    
    
    [Callstack]  03  0x000000000043596b  EngineCrashHandler(FGenericCrashContext const&) [/home/ioannis/VRSoftware/UnrealEngine/Engine/Source/Runtime/Launch/Private/Linux/LaunchLinux.cpp, line 31]
    [Callstack]  04  0x00007f31477cb571  PlatformCrashHandler(int, siginfo_t*, void*)
    [Callstack]  05  0x00007f31483048d0  /lib/x86_64-linux-gnu/libpthread.so.0(+0xf8d0) [0x7f31483048d0]
    [Callstack]  06  0x00007f31476fdc22  FGenericPlatformMisc::RaiseException(unsigned int)
    [Callstack]  07  0x00007f31477d88ea  FOutputDeviceLinuxError::Serialize(wchar_t const*, ELogVerbosity::Type, FName const&)
    [Callstack]  08  0x00007f31478b40b4  FOutputDevice::Logf(wchar_t const*, ...)
    [Callstack]  09  0x00007f3147892d10  FDebug::AssertFailed(char const*, char const*, int, wchar_t const*, ...)
    [Callstack]  10  0x00007f31477b58e6  FLinuxApplication::CreateLinuxApplication()
    [Callstack]  11  0x00007f31411ec14e  FSlateApplication::Create()
    [Callstack]  12  0x000000000041679d  FEngineLoop::PreInit(wchar_t const*) [/home/ioannis/VRSoftware/UnrealEngine/Engine/Source/Runtime/Launch/Private/LaunchEngineLoop.cpp, line 1336]
    [Callstack]  13  0x000000000042883f  GuardedMain(wchar_t const*) [/home/ioannis/VRSoftware/UnrealEngine/Engine/Source/Runtime/Launch/Private/Launch.cpp, line 31]
    [Callstack]  14  0x000000000043624f  ./UE4Editor(main+0x88f) [0x43624f] [/home/ioannis/VRSoftware/UnrealEngine/Engine/Source/Runtime/Launch/Private/Linux/LaunchLinux.cpp, line 193]
    [Callstack]  15  0x00007f313bf1fb45  /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5) [0x7f313bf1fb45]
    [Callstack]  16  0x0000000000412cd0  ./UE4Editor() [0x412cd0]
    
    [2015.12.09-10.29.57:663][  0]LogExit: Executing StaticShutdownAfterError
    Starting ../../../engine/binaries/linux/crashreportclient
    [2015.12.09-10.29.57:666][  0]LogGenericPlatformMisc: FPlatformMisc::RequestExit(1)
    Aborted (core dumped)

The computer is running Debian GNU/Linux 8 (jessie) on an Intel i5-3330 @ 3 Ghz, 8 gigs of RAM and 2x Quadro 600.
I’ve tried downloading both via git and zip, I’m not on the root user, and being an amateur Linux user, I’m at my wit’s end. Any help would be greatly appreciated.

This is the error:

[2015.12.09-10.29.57:511][  0]LogInit: Initializing SDL.
Xlib:  extension "RANDR" missing on display ":0".
[2015.12.09-10.29.57:560][  0]LogInit:Warning: Could not initialize SDL: XRandR support is required but not available       

Run “xrandr --version” command on your console to double check that you have RandR 1.4 or better.

Thanks for the reply. I get this when I run the command you recommended:
xrandr program version 1.4.2
RandR extension missing