enable AMD OpenCL sdk for linux too

Fixes Issue 641

Demos/SharedOpenCL/btOpenCLInclude.h

@@ -25,15 +25,13 @@ subject to the following restrictions:
 #endif
 #else
 #ifdef USE_MINICL
-#include <MiniCL/cl.h>
-#else
-#include <CL/cl.h>
-#ifdef _WIN32
-#include "CL/cl_gl.h"
-#endif //_WIN32
-#endif
-#endif //__APPLE__
-
+#include <MiniCL/cl.h>
+#else
+#include <CL/cl.h>
+#include <CL/cl_gl.h>
+#endif
+#endif //__APPLE__
+
 #include <assert.h>
 #include <stdio.h>
 #define oclCHECKERROR(a, b) if((a)!=(b)) { printf("OCL Error : %d\n", (a)); assert((a) == (b)); }