have the configure machinery remember XCODE_BASE
have the configure machinery remember XCODE_BASE

Reviewed By: jvillard

Differential Revision: D14619323

fbshipit-source-id: 89fa11e0e

jvillard/infer,facebook/infer,facebook/infer,jvillard/infer,jvillard/infer,facebook/infer,jvillard/infer,facebook/infer,facebook/infer,facebook/infer,jvillard/infer,jvillard/infer,jvillard/infer,facebook/infer