This patch has two components.

1. In tests/util/piglit-framework-gl.h, replace the definition of
PIGLIT_GL_TEST_MAIN with the macro block PIGLIT_GL_CONFIG_BEGIN/END.

The macro PIGLIT_GL_TEST_MAIN was very restrictive. It was a fixed-arity
macro function that allowed a test to set only set 3 values: window width,
height, and visual. It would have been difficult to shoehorn optional test
attributes into such a fixed-arity macro function. Allowing optional
attributes is an essential feature because a following commit adds
optional fields to struct piglit_gl_test_config.

The macro block PIGLIT_GL_TEST_CONFIG_BEGIN/END is more flexible. Within
it the test is allowed to arbitrarilty modify the piglit_gl_test_config
structure.

2. In each GL test source, replace PIGLIT_GL_TEST_MAIN with
a PIGLIT_GL_TEST_CONFIG_BEGIN/END block.

Reviewed-and-tested-by: Jordan Justen <jordan.l.justen@intel.com>
Tested-by: Paul Berry <stereotype441@gmail.com>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Chad Versace <chad.versace@linux.intel.com>