quartz: Fix build

Cairo cannot build with Quartz enabled since
573ddfc3d5c08c37b95a21e0a1b34acecc646053, because of a double
definition of _cairo_surface_is_quartz().

References: https://bugs.freedesktop.org/show_bug.cgi?id=84569
Signed-off-by: Andrea Canciani <ranma42@gmail.com>
quartz-image: Fix build

The quartz-image backend uses _cairo_surface_is_quartz(), which
therefore needs to be made available to it. Fixed as suggested by
Bryce in the referenced bugreport.

References: https://bugs.freedesktop.org/show_bug.cgi?id=84569
Signed-off-by: Andrea Canciani <ranma42@gmail.com>
quartz: Check for quartz surface type before conversion

Fixes the following warning introduced in a recent commit reported by
~suv:

  CC       cairo-quartz-image-surface.lo
cairo-quartz-image-surface.c:382:37: warning: incompatible pointer types
passing 'cairo_quartz_image_surface_t *'
      (aka 'struct cairo_quartz_image_surface *') to parameter of type
       'const cairo_surface_t *' (aka 'const struct _cairo_surface *')
      [-Wincompatible-pointer-types]
    if (! _cairo_surface_is_quartz (surface)) {
                                    ^~~~~~~
./cairo-quartz-private.h:87:50: note: passing argument to parameter 'surface' here
_cairo_surface_is_quartz (const cairo_surface_t *surface);

References:  https://bugs.freedesktop.org/show_bug.cgi?id=84569
Signed-off-by: Bryce Harrington <b.harrington@samsung.com>
Declare as private the new cairo_lines_compare_at_y symbol

Fixes a make check error.

  Checking that .libs/libcairo.so has the same symbol list as cairo.def
  126a127
  > cairo_lines_compare_at_y

Fixes:  https://bugs.freedesktop.org/show_bug.cgi?id=84638
Signed-off-by: Bryce Harrington <b.harrington@samsung.com>
Get make check back to a happy spot

Fix header ordering for some recently added code so cairo internal
headers are included first.  Quells two make check errors.

Fixes:  https://bugs.freedesktop.org/show_bug.cgi?id=84638