glsl/ast: Allow redeclaration of gl_Position and gl_PointSize with different precision qualifier.
In shaders using version 300 and when extension EXT_separate_shader_objects is required, redeclaration of gl_Position and gl_PointSize with different precision qualifier is allowed. This patch can solve the black screen issue of Android game FIFA caused by shader compile failure.
Signed-off-by: Xiaohui Gu xiaohui.gu@intel.com