gyp: fix regex to match multi-digit versions
gyp: fix regex to match multi-digit versions

This fixes the regular expression matching in `xcode_emulation`
to also handle version numbers with multiple-digit major versions
which would otherwise break under use of XCode 10

Fixes: https://github.com/nodejs/node-gyp/issues/1454
PR-URL: https://github.com/nodejs/node-gyp/pull/1455
Reviewed-By: Ben Noordhuis <59bd0a3ff43b32849b319e645d4798d8a5d1e889@bnoordhuis.nl>

refack/node-gyp,TooTallNate/node-gyp,refack/node-gyp,refack/node-gyp,TooTallNate/node-gyp,refack/node-gyp,TooTallNate/node-gyp,refack/node-gyp,TooTallNate/node-gyp,TooTallNate/node-gyp