Calculate specular lighting correctly

Since the lighting calculations are done in object space, the vector
from the object to the viewer also needs to be transformed to object
space.
diff --git a/include/private/opengles/gl_context.h b/include/private/opengles/gl_context.h
index 523aed0..67c2dd8 100644
--- a/include/private/opengles/gl_context.h
+++ b/include/private/opengles/gl_context.h
@@ -287,6 +287,7 @@
     vec4_t      normalizedObjPosition;
     vec4_t      spotDir;
     vec4_t      normalizedSpotDir;
+    vec4_t      objViewer;
     GLfixed     spotExp;
     GLfixed     spotCutoff;
     GLfixed     spotCutoffCosine;