diff --git a/Demos3/AllBullet2Demos/premake4.lua b/Demos3/AllBullet2Demos/premake4.lua
index eeac13583..436e1fa8d 100644
--- a/Demos3/AllBullet2Demos/premake4.lua
+++ b/Demos3/AllBullet2Demos/premake4.lua
@@ -48,7 +48,7 @@
 		"../GpuDemos/gwenUserInterface.h"
 		}
 
-if os.is("Linux") then links{"X11"} end
+if os.is("Linux") then links{"X11","pthread"} end
 if os.is("MacOSX") then
                         links{"Cocoa.framework"}
 end
diff --git a/Demos3/GpuDemos/premake4.lua b/Demos3/GpuDemos/premake4.lua
index 24ca2eaf2..77e2f7119 100644
--- a/Demos3/GpuDemos/premake4.lua
+++ b/Demos3/GpuDemos/premake4.lua
@@ -91,7 +91,7 @@ function createProject(vendor)
 			}
 		end
 		if os.is("Linux") then
-			links{"X11"}
+			links{"X11","pthread"}
 			files {
 				"../../btgui/OpenGLWindow/X11OpenGLWindow.cpp",
 				"../../btgui/OpenGLWindow/X11OpenGLWindows.h"
diff --git a/Demos3/GpuGuiInitialize/premake4.lua b/Demos3/GpuGuiInitialize/premake4.lua
index 696235966..b36da7dd5 100644
--- a/Demos3/GpuGuiInitialize/premake4.lua
+++ b/Demos3/GpuGuiInitialize/premake4.lua
@@ -68,7 +68,7 @@ function createProject(vendor)
 			}
 		end
 		if os.is("Linux") then
-			links {"X11"}
+			links {"X11","pthread"}
 			files {
 				"../../btgui/OpenGLWindow/X11OpenGLWindow.cpp",
 				"../../btgui/OpenGLWindow/X11OpenGLWindows.h"
diff --git a/Demos3/ImplicitCloth/premake4.lua b/Demos3/ImplicitCloth/premake4.lua
index 8eea82ce3..beb20168d 100644
--- a/Demos3/ImplicitCloth/premake4.lua
+++ b/Demos3/ImplicitCloth/premake4.lua
@@ -61,6 +61,7 @@ if os.is("Windows") then
 		"../../btgui/OpenGLWindow/X11OpenGLWindow.h",
 		"../../btgui/OpenGLWindow/X11OpenGLWindow.cpp"
 		}
+		links{"pthread"}
 	end
 	if os.is("MacOSX") then
 		links{"Cocoa.framework"}
diff --git a/Demos3/SimpleOpenGL3/premake4.lua b/Demos3/SimpleOpenGL3/premake4.lua
index 2ab575f07..57a2a04f7 100644
--- a/Demos3/SimpleOpenGL3/premake4.lua
+++ b/Demos3/SimpleOpenGL3/premake4.lua
@@ -27,7 +27,7 @@
 
 		}
 		
-if os.is("Linux") then links {"X11"} end
+if os.is("Linux") then links {"X11","pthread"} end
 
 if os.is("MacOSX") then
 	links{"Cocoa.framework"}
diff --git a/btgui/GwenOpenGLTest/premake4.lua b/btgui/GwenOpenGLTest/premake4.lua
index fb39dcbfe..1bca96bc8 100644
--- a/btgui/GwenOpenGLTest/premake4.lua
+++ b/btgui/GwenOpenGLTest/premake4.lua
@@ -55,6 +55,7 @@
 		"../OpenGLWindow/X11OpenGLWindow.h",
 		"../OpenGLWindow/X11OpenGLWindow.cpp"
 		}
+		links{"pthread"}
 	end
 	if os.is("MacOSX") then
 		links{"Cocoa.framework"}
diff --git a/btgui/OpenGLWindow/X11OpenGLWindow.cpp b/btgui/OpenGLWindow/X11OpenGLWindow.cpp
index 0a525b081..6b5bcb39d 100644
--- a/btgui/OpenGLWindow/X11OpenGLWindow.cpp
+++ b/btgui/OpenGLWindow/X11OpenGLWindow.cpp
@@ -11,6 +11,8 @@
 
 #include <stdio.h>
 
+#include <pthread.h>
+
 GLint                   att[] = { GLX_RGBA, GLX_DEPTH_SIZE, 24, GLX_DOUBLEBUFFER, None };
 
 
@@ -82,6 +84,13 @@ void X11OpenGLWindow::enableOpenGL()
     printf("GL_VERSION=%s\n", ver);
     const GLubyte* sl = glGetString(GL_SHADING_LANGUAGE_VERSION);
     printf("GL_SHADING_LANGUAGE_VERSION=%s\n", sl);
+
+//Access pthreads as a workaround for a bug in Linux/Ubuntu
+//See https://bugs.launchpad.net/ubuntu/+source/nvidia-graphics-drivers-319/+bug/1248642
+
+	int i=pthread_getconcurrency();
+        printf("pthread_getconcurrency()=%d\n",i);
+
 //    const GLubyte* ext = glGetString(GL_EXTENSIONS);
 //    printf("GL_EXTENSIONS=%s\n", ext);
 }
diff --git a/btgui/OpenGLWindow/premake4.lua b/btgui/OpenGLWindow/premake4.lua
index be45bbe0d..b6c869646 100644
--- a/btgui/OpenGLWindow/premake4.lua
+++ b/btgui/OpenGLWindow/premake4.lua
@@ -30,7 +30,9 @@
       	"Win32Window.h",
 			}
 		end
-		if not os.is("Linux") then
+		if os.is("Linux") then
+			links {"pthread"}
+		else
 			excludes {
 				"X11OpenGLWindow.cpp",
 				"X11OpenGLWindows.h"