I found this article was a bit out of date and found out why some people were building with ./config flame:
I updated the wiki some; perhaps this might curb the mistakes when building on OS X.
Also to note, there was a B2G patch for the Mac OS X bootstrap code, I pushed for a contributor after getting a review+ on the code from a Moz Dev. This is so that 10.10 is now accounted for.
In case you're wondering, I got a 10.10 machine and I'm doing some build testing on it.