x86int: use extern to avoid duplicate symbol linker errors
x86int: use extern to avoid duplicate symbol linker errors

luctrudeau/daala,KyleSiefring/daala,xiph/daala,xiphmont/daala,ycho/daala,ycho/daala,luctrudeau/daala,xiph/daala,xiphmont/daala,HeadhunterXamd/daala,xiph/daala,KyleSiefring/daala,xiphmont/daala,KyleSiefring/daala,HeadhunterXamd/daala,jmvalin/daala,jmvalin/daala,HeadhunterXamd/daala,xiphmont/daala,xiph/daala,luctrudeau/daala,kodabb/daala,jmvalin/daala,ycho/daala,HeadhunterXamd/daala,kodabb/daala,jmvalin/daala,xiph/daala,luctrudeau/daala,KyleSiefring/daala,kodabb/daala,kodabb/daala,luctrudeau/daala,kodabb/daala,HeadhunterXamd/daala,KyleSiefring/daala,xiphmont/daala,ycho/daala,jmvalin/daala,ycho/daala