Import elftoolchain rev 3130

From svn.code.sf.net/p/elftoolchain/code/trunk
Copy elftoolchain top-level directory from vendor at r260684

Subdirectories are copied from r276062.

This will allow 'svn merge' at the elftoolchain top level to work
properly. Previously only the subdirectories were related to the vendor
branch according to svn metadata, which meant they would have to be
merged individually.
Update elftoolchain to upstream rev 3130

This brings a number of fixes to elfcopy/strip and DWARF4 improvements.

Sponsored by:	The FreeBSD Foundation
Update elftoolchain to upstream rev 3130

This includes a number of libdwarf improvements (particularly DWARF4
related) and updates to elftoolchain tools such as strip(1). It also
includes a large number of miscellaneous fixes (memory leaks, sign and
cast warnings, integer overflow and underflow, etc.).

This is a merge of r276167,276170-276172 from the
projects/elftoolchain-update-r3130 branch.

Sponsored by:	The FreeBSD Foundation