[binutils-gdb] Use memcpy in minimal_symbol_reader::install

[sergiodj+buildbot at sergiodj dot net]

*** TEST RESULTS FOR COMMIT 0de2420c4b023e644f91a409803fedfb235bfc0b ***

Author: Tom Tromey <tom@tromey.com>
Branch: master
Commit: 0de2420c4b023e644f91a409803fedfb235bfc0b

Use memcpy in minimal_symbol_reader::install

minimal_symbol_reader::install copies minsyms from the msym_bunch
objects into the allocated memory.  It seemed better to me to do this
via memcpy, as that is frequently optimized in libc.

gdb/ChangeLog
2019-03-15  Tom Tromey  <tom@tromey.com>

	* minsyms.c (minimal_symbol_reader::install): Use memcpy.