apply patch, so that gdb supports golang on mac

This patch adds functionality to the Mach-O reader to be aware of the .debug_gdb_scripts section produced in Mac OS X binaries by the Go toolchain. 

refer to https://github.com/sirnewton01/godbg#mac-os-x
and http://sourceware-org.1504.n7.nabble.com/Path-Add-support-for-mach-o-reader-to-be-aware-of-debug-gdb-scripts-td238372.html