Log Message:
Changes 1.12.16:
Bug fixes
* Set the correct orientation for simple boxes with a negative scale factor.
* Fix the creation of the shading dictionary in PDF.
* Fix a crash in PDF when incorporating an image with CAIRO_EXTEND_PAD.
* Avoid upscaling bitmap fonts if possible.
* Fix an assertion failure within the mempool allocator for shared memory.
* Fix allocation size for CFF subsets.
* Export cairo_matrix_t for GObject bindings.
* Fix a double free in the Quartz backend.
* Fix origin of GDI StretchBlits for the Windows backend
* Fix error propagation for requests to create a similar surface with
  negative size.
* Fix complex clipping of trapezoids with regions
* Stop leaking the image data when loading PNGs
* Fix unbounded operations with a clip mask through the span compositor
* Add missing checks before rendering to a finished surface - so we return
  an error rather than hit an assert.
* Prevent an assertion failure when creating similar GL surfaces larger
  than supported by hardware.
* Prevent a double free of a similar image under Windows.