move build to build3 to avoid naming conflict with Bullet 2.x

fix build error in BasicGpuDemo
Thanks to joen66 for the report here:
https://github.com/erwincoumans/bullet3/issues/5

build3/findOpenCL.lua

@@ -0,0 +1,175 @@
+
+	function findOpenCL_clew()
+		return true;
+	end
+
+	function findOpenCL_Apple()
+		if os.is("macosx") then
+			return true	
+		else
+			return false
+		end
+	end
+
+	
+	function findOpenCL_AMD()
+		local amdopenclpath = os.getenv("AMDAPPSDKROOT")
+		if (amdopenclpath) then
+			return true
+		end
+		return false
+	end
+
+	function findOpenCL_NVIDIA()
+		local nvidiaopenclpath = os.getenv("CUDA_PATH")
+		if (nvidiaopenclpath) then
+			return true
+		end
+		return false
+	end
+
+	function findOpenCL_Intel()
+		if os.is("Windows") then
+			local intelopenclpath = os.getenv("INTELOCLSDKROOT")
+			if (intelopenclpath) then
+			return true
+			end
+		end
+		if os.is("Linux") then
+			local intelsdk = io.open("/usr/include/CL/opencl.h","r")
+			if (intelsdk) then
+				return true;
+			end
+		end
+		return false
+	end
+		
+	function initOpenCL_clew()
+		configuration{}
+		includedirs {
+			projectRootDir .. "src/clew"
+		}
+		defines {"B3_USE_CLEW"}
+		files {
+			projectRootDir .. "src/clew/clew.c",
+			projectRootDir .. "src/clew/clew.h"
+		}
+		 if os.is("Linux") then
+        	        links {"dl"}
+        	end
+	end
+
+	function initOpenCL_Apple()
+		configuration{}
+		includedirs {
+			"/System/Library/Frameworks/OpenCL.framework"
+		}
+		libdirs "/System/Library/Frameworks/OpenCL.framework"
+		links
+		{
+			"OpenCL.framework"
+		}
+	end
+	
+	function initOpenCL_AMD()
+		configuration {}
+		local amdopenclpath = os.getenv("AMDAPPSDKROOT")
+		if (amdopenclpath) then
+			defines { "ADL_ENABLE_CL" , "CL_PLATFORM_AMD"}
+			includedirs {
+				"$(AMDAPPSDKROOT)/include"				
+			}
+			configuration "x32"
+				libdirs {"$(AMDAPPSDKROOT)/lib/x86"}
+			configuration "x64"
+				libdirs {"$(AMDAPPSDKROOT)/lib/x86_64"}
+			configuration {}
+			links {"OpenCL"}
+			return true
+		end
+		return false
+	end
+
+
+	function initOpenCL_NVIDIA()
+		configuration {}
+		local nvidiaopenclpath = os.getenv("CUDA_PATH")
+		if (nvidiaopenclpath) then
+			defines { "ADL_ENABLE_CL" , "CL_PLATFORM_NVIDIA"}
+			includedirs {
+				"$(CUDA_PATH)/include"				
+			}
+			configuration "x32"
+				libdirs {"$(CUDA_PATH)/lib/Win32"}
+			configuration "x64"
+				libdirs {"$(CUDA_PATH)/lib/x64"}
+			configuration {}
+			links {"OpenCL"}
+			return true
+		end
+		return false
+	end
+
+	function initOpenCL_Intel()
+		configuration {}
+		if os.is("Windows") then
+		local intelopenclpath = os.getenv("INTELOCLSDKROOT")
+		if (intelopenclpath) then
+			defines { "ADL_ENABLE_CL" , "CL_PLATFORM_INTEL"}
+			includedirs {
+				"$(INTELOCLSDKROOT)/include"				
+			}
+			configuration "x32"
+				libdirs {"$(INTELOCLSDKROOT)/lib/x86"}
+			configuration "x64"
+				libdirs {"$(INTELOCLSDKROOT)/lib/x64"}
+			configuration {}
+			links {"OpenCL"}
+			return true
+		end
+		end
+		if os.is("Linux") then
+			defines { "ADL_ENABLE_CL" , "CL_PLATFORM_INTEL"}
+                        configuration {}
+                        links {"OpenCL"}
+		end
+		return false
+	end
+	
+	function findOpenCL (vendor )
+		if vendor=="clew" then
+			return findOpenCL_clew()
+		end
+		if vendor=="AMD" then
+			return findOpenCL_AMD()
+		end
+		if vendor=="NVIDIA" then
+			return findOpenCL_NVIDIA()
+		end
+			if vendor=="Intel" then
+			return findOpenCL_Intel()
+		end
+		if vendor=="Apple" then
+			return findOpenCL_Apple()
+		end
+		return false
+	end
+	
+	function initOpenCL ( vendor )
+		if vendor=="clew" then
+			initOpenCL_clew()
+		end
+		if vendor=="AMD" then
+			initOpenCL_AMD()
+		end
+		if vendor=="NVIDIA" then
+			return initOpenCL_NVIDIA()
+		end
+		if vendor=="Intel" then
+			initOpenCL_Intel()
+		end
+		if vendor=="Apple" then
+			return initOpenCL_Apple()
+		end
+	end
+