Add x86_64/x86 support

[mbroadst]

Hey guys, I'm pretty sure there's a better way to handle this but I figured I'd start the conversation here. Yocto generally defines ia32/x64 as x86/x86_64, which generally wouldn't be a problem (I would just override these values in the recipe itself), however when node-ffi is brought in as a dependency I have less control over the situation since npm is sort of "in charge".

The easiest solution seemed to be to just copy those configurations and that allows the build to proceed, however I could see benefit to adding some logic to the gyp file to eliminate the need for duplicating the files. I'm no gyp expert, so maybe some advice here would be helpful.

Cheers!

[TooTallNate]

This seems more like a gyp / node-gyp issue. x86 should map to ia32 and x86_64 should map to x64. Could you try making an issue at https://github.com/nodejs/node-gyp/issues ?

[mbroadst]

@TooTallNate actually this looks to be a problem with the meta-nodejs layer for yocto, we already have a method there for converting the arch strings it just wasn't used for the npm bbclass. Sorry for the noise.