libjpeg_turbo: Filter out "section flags ignored on section redeclaration" warnings on mac.

libjpeg_turbo: Filter out "section flags ignored on section redeclaration" warnings on mac.

This removes over 50 lines of warning output when doing a clobber build on mac.

Thanks to mark@ for telling me how to get >() process substitution work with gyp.
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=124240

[Hironori Bono, 2012-02-29 07:31:09]

LGTM.
Thanks for your fix. (It may be better to fix 'jsimdext.inc'?)

Regards,

Hironori Bono

[Nico, 2012-02-29 20:23:49]

Thank you for your review!

On 2012/02/29 07:31:09, Hironori Bono wrote:
> (It may be better to fix 'jsimdext.inc'?)

I couldn't think of a good way. The .inc file basically says

  #if mac
  SECTION SEG_CONST
    stuff
  #endif

which means the asm file with the include looks like

  #if mac
  SECTION SEG_CONST
    stuff
  #endif

  SECTION SEG_CONST

I could change all the .asm files so that they look like this after the include
has been processes:

  #if mac
  SECTION SEG_CONST
    stuff
  #endif

  #if not mac
  SECTION SEG_CONST
  #else
  .rodata
  #endif

…but that requires changing many files, and all asm files needs to be updated if
someone removes the mac-specific SEG_CONST from the inc file in the future.

I think the correct fix would be to change yasm to not warn on ignored section
flags if they match the flags on the first declaration of a section, but I'm not
familiar enough with yasm to do that.

[Nico, 2012-02-29 20:33:16]

(I filed http://tortall.lighthouseapp.com/projects/78676-yasm/tickets/246 on the
yasm bug tracker.)