Add sanity checking feature.
Add sanity checking.
Add prototypes.
New functions.
New function.
Use fixed functions. (_cairo_gstate_clip): Arithmetic fixes. (_cairo_gstate_clip_and_composite_trapezoids): (_cairo_gstate_show_surface): (_cairo_gstate_show_text): (_cairo_gstate_show_glyphs): Corrections to clipping.
Add XCopyArea fast path. (_cairo_xlib_surface_set_clip_region): Drive clip to drawable.