I was able to successfully compile libjpeg-turbo on an arm system. However, libjpeg-turbo hard-depends on nasm - nasm is x86/amd64-only, so the dep on nasm is obviously not required on non-intel archs. Please limit the nasm dependency in libjpeg-turbo to x86/amd64.
I suspected that much but didn't want to rush it before next release (when jpeg-8c has been catched up and the jpegoptim regression fixed)
+ 07 May 2011; Samuli Suominen <ssuominen@gentoo.org> + libjpeg-turbo-1.1.0.ebuild: + Limit dev-lang/nasm DEPEND to amd64/x86/amd64-linux/and x86-linux wrt + #364985.