diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7e48e120f..f590169dd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -131,7 +131,12 @@ ENDIF(INTERNAL_CREATE_MSVC_RELATIVE_PATH_PROJECTFILES)
 
 ENDIF (WIN32)
 
-OPTION(BUILD_MINICL_OPENCL_DEMOS "Build OpenCL demos for MiniCL (Generic CPU)"  ON)
+IF (WIN32 OR APPLE)
+	OPTION(BUILD_MINICL_OPENCL_DEMOS "Build OpenCL demos for MiniCL (Generic CPU)"  ON)
+ELSE()
+#there is some build problem, locating glew under Linux
+	OPTION(BUILD_MINICL_OPENCL_DEMOS "Build OpenCL demos for MiniCL (Generic CPU)" OFF)
+ENDIF()
 
 OPTION(BUILD_CPU_DEMOS "Build original Bullet CPU demos"        ON)
 
diff --git a/Demos/ParticlesOpenCL/MiniCL/CMakeLists.txt b/Demos/ParticlesOpenCL/MiniCL/CMakeLists.txt
index 560795265..1b2266814 100644
--- a/Demos/ParticlesOpenCL/MiniCL/CMakeLists.txt
+++ b/Demos/ParticlesOpenCL/MiniCL/CMakeLists.txt
@@ -8,6 +8,10 @@ ${BULLET_PHYSICS_SOURCE_DIR}/Demos/OpenGL
 
 ADD_DEFINITIONS(-DUSE_MINICL)
 
+#to get this to compile under linux, you could try setting CMAK_GLEW_LIBRARY
+#to  /usr/lib/libGLEW.so
+
+
 IF(WIN32)
 IF (CMAKE_CL_64)
 	SET(CMAK_GLEW_LIBRARY	${BULLET_PHYSICS_SOURCE_DIR}/Glut/glew64.lib	)
diff --git a/Demos/Raytracer/Raytracer.cpp b/Demos/Raytracer/Raytracer.cpp
index 95e9833b0..7d78901cc 100644
--- a/Demos/Raytracer/Raytracer.cpp
+++ b/Demos/Raytracer/Raytracer.cpp
@@ -491,7 +491,7 @@ extern unsigned char sFontData[];
 	if (0)
 	{
 
-		char* text="ABC abc 123 !@#";
+		const char* text="ABC abc 123 !@#";
 			int x=0;
 		for (int cc = 0;cc<strlen(text);cc++)
 		{
diff --git a/Demos/ThreadingDemo/main.cpp b/Demos/ThreadingDemo/main.cpp
index a828dc6cd..0bd6d6838 100644
--- a/Demos/ThreadingDemo/main.cpp
+++ b/Demos/ThreadingDemo/main.cpp
@@ -24,9 +24,10 @@ void	SampleThreadFunc(void* userPtr,void* lsMemory);
 void*	SamplelsMemoryFunc();
 
 #include <stdio.h>
+#include "BulletMultiThreaded/PlatformDefinitions.h"
 
-
-#ifdef __APPLE__
+#ifdef USE_PTHREADS
+//#ifdef __APPLE__
 #include "BulletMultiThreaded/PosixThreadSupport.h"
 
 btThreadSupportInterface* createThreadSupport(int numThreads)
diff --git a/src/BulletMultiThreaded/MiniCL.cpp b/src/BulletMultiThreaded/MiniCL.cpp
index 56519013f..203722f93 100644
--- a/src/BulletMultiThreaded/MiniCL.cpp
+++ b/src/BulletMultiThreaded/MiniCL.cpp
@@ -27,7 +27,7 @@ subject to the following restrictions:
 #include "LinearMath/btMinMax.h"
 #include <stdio.h>
 
-#define DEBUG_MINICL_KERNELS 1
+//#define DEBUG_MINICL_KERNELS 1
 
 static char* spPlatformID = "MiniCL, SCEA";
 
diff --git a/src/BulletMultiThreaded/PosixThreadSupport.h b/src/BulletMultiThreaded/PosixThreadSupport.h
index 588d9e2a7..13e519b54 100644
--- a/src/BulletMultiThreaded/PosixThreadSupport.h
+++ b/src/BulletMultiThreaded/PosixThreadSupport.h
@@ -18,7 +18,9 @@ subject to the following restrictions:
 #include "PlatformDefinitions.h"
 
 #ifdef USE_PTHREADS  //platform specific defines are defined in PlatformDefinitions.h
+#ifndef _XOPEN_SOURCE
 #define _XOPEN_SOURCE 600 //for definition of pthread_barrier_t, see http://pages.cs.wisc.edu/~travitch/pthreads_primer.html
+#endif //_XOPEN_SOURCE
 #include <pthread.h>
 #include <semaphore.h>