[cairo] towards 24.8

[Vladimir Vukicevic]

I was seeing some very odd performance behaviour under OSX, but now I'm 
thinking it was due to cairo-perf not being bound to a specific CPU in 
my dual-core Mac Mini.  Below are my results after a few runs on a quiet 
machine, under X, i810 driver.  Note that I didn't make any changes from 
when cworth ran his tests (other than a compilation fix in the quartz 
surface), so I'm not sure why I'm seeing such different results.  But 
this is more in line with what I'd expect (+/- a few %, though some of 
the speedups are strange -- I guess inlining all the fixed math 
functions helped quite a bit in some cases).

So, what do you guys think -- should I merge this in to the mainline?

    - Vlad

Speedups
========
image-rgb               subimage_copy-256    0.00 0.18% ->   0.00 2.54%: 
  1.11x speedup
▏
  xlib-rgba          long-dashed-lines-512   60.01 0.36% ->  55.30 
0.94%:  1.10x speedup
▏
image-rgb           long-dashed-lines-512   60.33 0.26% ->  55.47 0.76%: 
  1.10x speedup
▏
image-rgba          long-dashed-lines-512   60.09 0.13% ->  55.61 0.75%: 
  1.10x speedup
▏
  xlib-rgb           long-dashed-lines-512   61.78 0.84% ->  56.81 
0.80%:  1.09x speedup
▏
image-rgb        paint_image_rgb_over-256    0.09 4.81% ->   0.08 2.52%: 
  1.07x speedup
▏
image-rgb      paint_image_rgb_source-256    0.09 5.11% ->   0.08 2.89%: 
  1.07x speedup
▏
image-rgb        paint_solid_rgb_over-512    0.39 10.32% ->   0.37 
3.05%:  1.07x speedup
▏
image-rgb      paint_solid_rgb_source-512    0.38 1.66% ->   0.37 3.74%: 
  1.07x speedup
▏
image-rgb     paint_solid_rgba_source-512    0.38 1.53% ->   0.36 3.23%: 
  1.06x speedup
▏
  xlib-rgb       pattern_create_radial-16     3.96 2.94% ->   3.55 
1.82%:  1.06x speedup
▏
image-rgba    paint_image_rgba_source-512    0.62 2.13% ->   0.61 3.58%: 
  1.06x speedup

  xlib-rgba   paint_radial_rgba_source-512   37.42 0.12% ->  37.39 
5.39%:  1.06x speedup

  xlib-rgba    paint_radial_rgb_source-512   37.42 0.16% ->  35.56 
1.90%:  1.06x speedup

image-rgba              subimage_copy-16     0.00 1.17% ->   0.00 1.10%: 
  1.06x speedup

image-rgb    mosaic_tessellate_curves-800   68.23 0.21% ->  64.38 0.16%: 
  1.06x speedup

  xlib-rgb    mosaic_tessellate_curves-800   68.54 0.55% ->  64.25 
0.46%:  1.06x speedup

image-rgba paint-with-alpha_radial_rgba_over-256    9.66 2.67% ->   9.08 
0.03%:  1.06x speedup

  xlib-rgba   mosaic_tessellate_curves-800   68.34 0.22% ->  64.45 
0.12%:  1.06x speedup

image-rgba              subimage_copy-64     0.00 0.28% ->   0.00 0.96%: 
  1.06x speedup

image-rgba     fill_radial_rgb_source-256    4.34 0.31% ->   4.11 0.05%: 
  1.06x speedup

  xlib-rgba     paint_radial_rgba_over-512   39.56 0.17% ->  39.50 
5.13%:  1.06x speedup

image-rgba   mosaic_tessellate_curves-800   68.11 0.29% ->  64.42 0.16%: 
  1.06x speedup

image-rgb               subimage_copy-32     0.00 0.59% ->   0.00 1.20%: 
  1.05x speedup

image-rgb               subimage_copy-128    0.00 0.41% ->   0.00 0.90%: 
  1.05x speedup

image-rgb     paint_radial_rgb_source-512   33.42 1.29% ->  31.13 0.45%: 
  1.05x speedup

image-rgba      fill_radial_rgba_over-128    1.11 0.10% ->   1.10 1.83%: 
  1.05x speedup

  xlib-rgba      pattern_create_radial-16     3.87 2.15% ->   3.61 
1.70%:  1.05x speedup

Slowdowns
=========
image-rgba    paint_radial_rgb_source-512   31.14 0.51% ->  33.24 0.44%: 
  1.07x slowdown
▏
image-rgba      paint_radial_rgb_over-512   31.50 0.21% ->  33.56 0.19%: 
  1.07x slowdown
▏