Fixed Mac build

The Linux build fix had broken the Mac build, so the new
"typeinfo" virtual function were moved from the header files
to the source files to fix both builds simultaneously.

Change-Id: I37f5ef4bd5ec4da34a19531dcb85df6a98728aa1
Reviewed-on: https://swiftshader-review.googlesource.com/8748
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
diff --git a/src/OpenGL/common/Image.cpp b/src/OpenGL/common/Image.cpp
index c734ba2..cd27753 100644
--- a/src/OpenGL/common/Image.cpp
+++ b/src/OpenGL/common/Image.cpp
@@ -1178,6 +1178,8 @@
 		}
 	}
 
+	void Image::typeinfo() {}
+
 	Image::~Image()
 	{
 		if(parentTexture)