[PATCH] Initial DWARF64 support for .debug_line

[Ed Maste]

  FreeBSD in-tree toolchain updated in svn r256859:
  http://svnweb.freebsd.org/base?view=revision&revision=256859

  Shall I still proceed with this patch?  We (a) have objects with 64-bit dwarf .debug_line already due to the silly default in older toolchains, and (b) may eventually encounter an object that actually requires this support.

http://llvm-reviews.chandlerc.com/D1988