fix macOS stack trace regression

f8f054b354088eb9e76d9207972022bc1d3dfc28 exposes the issue where
macho symbol `__mh_execute_header` is weak exported with an extra
underscore and stack traces fail due to invalid header magic.

related #2700
60b1cf2a83Michael Dusan committed on 6/20/2019, 11:29:25 PM· committed by Andrew Kelleyparent381c6a3
1 file changedLine totals unavailable