I was updating world on a netbook that hasn't been updated in a few months and got this pre-merge check failure. I had just emerged sys-devel/gcc-5.3.0-r1 on this netbook the day before. This bug has been fixed in Gentoo, apparently, with a patch. Though gcc 5.4.0 is out now, so that may be an option too.

>>> Running pre-merge checks for app-emulation/wine-1.9.13

• Checking for gcc-5-3 stack realignment compiler bug ... [ !! ]
• Wine cannot be built with this version of gcc-5.3
• due to compiler bugs; please re-emerge the latest gcc-5.3.x ebuild,
• or use gcc-config to select a different compiler version.
• See https://bugs.gentoo.org/574044
• ERROR: app-emulation/wine-1.9.13::gentoo failed (pretend phase):
• (no error message)
• Call stack:
• ebuild.sh, line 133: Called pkg_pretend
• wine-1.9.13.ebuild, line 250: Called die
• The specific snippet of code:
• wine_compiler_check || die
• If you need support, post the output of `emerge --info '=app-emulation/wine-1.9.13::gentoo'`,
• the complete build log and the output of `emerge -pqv '=app-emulation/wine-1.9.13::gentoo'`.
• The complete build log is located at '/var/tmp/portage/app-emulation/wine-1.9.13/temp/build.log'.
• The ebuild environment file is located at '/var/tmp/portage/app-emulation/wine-1.9.13/temp/die.env'.
• Working directory: '/var/tmp/portage/.portage_reinstall.jkbbi6iy/pym'
• S: '/var/tmp/portage/app-emulation/wine-1.9.13/work/wine-1.9.13'