Originally reported in
https://bugzilla.redhat.com/show_bug.cgi?id=1577396 -- gdb build fails
with Python 3.7 due to references to a Python internal function whose
declaration changed in 3.7.

gdb/ChangeLog
2018-06-09  Paul Koning  <paul_koning@dell.com>

	    PR gdb/23252

	    * python/python.c (do_start_initialization):
	    Avoid call to internal Python API.
	    (init__gdb_module): New function.