libbacktrace patch committed: Fix setting str_size on PE/COFF

[Ian Lance Taylor]

This libbacktrace patch fixes the setting of str_size on PE/COFF to
not leave some bytes uninitialized on a 64-bit host.  Committed to
mainline.

Ian

2018-01-24  Ian Lance Taylor  <i...@golang.org>

* pecoff.c (coff_add): Use coff_read4, not memcpy.

Index: pecoff.c
===================================================================
--- pecoff.c    (revision 257038)
+++ pecoff.c    (working copy)
@@ -727,7 +727,7 @@ coff_add (struct backtrace_state *state,
        goto fail;
       syms_view_valid = 1;
 
-      memcpy (&str_size, syms_view.data + syms_size, 4);
+      str_size = coff_read4 (syms_view.data + syms_size);
 
       str_off = syms_off + syms_size;