Updates #11

Fixes #3

Fixes #1

	on the free list.

Fixes #5
Fixes rust-lang/rust#29293
Fixes rust-lang/rust#37477

Add required support files to the config subdirectory.

Update dtest to be based on a statically linked program.

This brings in this patch:

	* elf.c (codes) [GENERATE_FIXED_HUFFMAN_TABLE]: Fix size to be
	288.
	(main) [GENERATE_FIXED_HUFFMAN_TABLE]: Pass 288 to
	elf_zlib_inflate_table.  Generate elf_zlib_default_dist_table.
	(elf_zlib_default_table): Update.
	(elf_zlib_default_dist_table): New static array.
	(elf_zlib_inflate): Use elf_zlib_default_dist_table for dist table
	for block type 1.
	* ztest.c (struct zlib_test): Add uncompressed_len.
	(tests): Initialize uncompressed_len field.  Add new test case.
	(test_samples): Use uncompressed_len field.

Previous change (update from gcc trunk) broke 'make install'; this
corrects the problem.

Includes (among other things) support for compressed debug sections,
a variety of bugfixes, and expanded test coverage.

Fixes #4

This is a standalone version of the libbacktrace library that I
originally wrote for GCC.  This is a copy of libbacktrace from GCC
trunk, with all dependencies incorporated here.