Merge commit 'f668afd4'

* commit 'f668afd4':
  swscale: fix "ISO C90 forbids mixed declarations and code" warning
  swscale: fix compilation with --enable-runtime-cpudetect
  swscale: correct include path to fix ppc altivec build
  swscale: simplify rgb2rgb templating
  swscale: simplify initialization code
  swscale: further cleanup swscale.c
  swscale: partially move the arch specific code left
  swscale: move away x86 specific code from rgb2rgb

None of above is merged, the changes are not yet ready they add over 2000 lines of duplicated code and a few bugs
Merged-by: Michael Niedermayer <michaelni@gmx.at>