modules/video_filter/deinterlace/algo_yadif.c does not compile with gcc 4.8 with -fstack-check on x86

This comes from a downstream bug:

https://bugs.gentoo.org/show_bug.cgi?id=499996

Specifically, here's the gcc error:

In file included from deinterlace/yadif.h:49:0,
                 from deinterlace/algo_yadif.c:48:
deinterlace/yadif_template.h: In function 'yadif_filter_line_ssse3':
deinterlace/yadif_template.h:134:9: error: 'asm' operand has impossible constraints
         __asm__ volatile(\
         ^
deinterlace/yadif_template.h:256:9: note: in expansion of macro 'FILTER'
         FILTER
         ^

yadif_template.h was originally yadif_template.c from ffmpeg (libavfilter). The ffmpeg version has since been converted to YASM syntax, so unfortunately it's not so easy to copy changes over from there. However, I still suspect that this commit may be relevant:

http://git.videolan.org/?p=ffmpeg.git;a=commit;h=67360ccd51f37a6a4f31363f1c9fc46f43a22cb8

I'm throwing this out there in the hopes that someone else can easily see the problem and/or reproduce, because I actually don't have a machine at hand to do so myself. (This report is more a favor to Gentoo, rather than a problem I have myself.)