Bug 20970 - Add a --annotate option to abidw

Bug 20970 - Add a --annotate option to abidw

This option annotates (read "pretty-prints") the types and elf symbols
in the form of XML comments in the ABIXML output emitted by the abidw
command.

Signed-off-by: Ondrej Oprala <ondrej.oprala@gmail.com>
	* doc/manuals/abidiff.rst: Document the '--no-corpus-path'
	option.
	* doc/manuals/abidw.rst: Document the '--no-corpus-path'
	and '--annotate' options.
	* include/abg-libxml-utils.h ({un,}escape_xml_comment): Add
	new function declarations.
	* include/abg-writer.h: Add new annotate functions
	(write_{translation_unit,corpus_to_{archive,native_xml_file}}):
	Add an optional "annotate" parameter defaulting to "false".
	* src/abg-libxml-utils.cc ({un,}escape_xml_comment): Add
	new function definitions.
	* src/abg-writer.cc (annotate): Define new templatized function
	and specialize it for necessary cases.
	* tests/Makefile.am: Add runtestannotate as a new test.
	* tests/data/Makefile.am: Add paths to below reference test
	outputs.
	* tests/data/test-annotate/libtest23.so.abi: New reference test
	output.
	* tests/data/test-annotate/libtest24-drop-fns-2.so.abi: Likewise.
	* tests/data/test-annotate/libtest24-drop-fns.so.abi: Likewise.
	* tests/data/test-annotate/test0.abi: Likewise.
	* tests/data/test-annotate/test1.abi: Likewise.
	* tests/data/test-annotate/test10-pr18818-gcc.so.abi: Likewise.
	* tests/data/test-annotate/test11-pr18828.so.abi: Likewise.
	* tests/data/test-annotate/test12-pr18844.so.abi: Likewise.
	* tests/data/test-annotate/test13-pr18894.so.abi: Likewise.
	* tests/data/test-annotate/test14-pr18893.so.abi: Likewise.
	* tests/data/test-annotate/test15-pr18892.so.abi: Likewise.
	* tests/data/test-annotate/test16-pr18904.so.abi: Likewise.
	* tests/data/test-annotate/test17-pr19027.so.abi: Likewise.
	* tests/data/test-annotate/test18-pr19037-libvtkRenderingLIC-6.1.so.abi: Likewise.
	* tests/data/test-annotate/test19-pr19023-libtcmalloc_and_profiler.so.abi: Likewise.
	* tests/data/test-annotate/test2.so.abi: Likewise.
	* tests/data/test-annotate/test20-pr19025-libvtkParallelCore-6.1.so.abi: Likewise.
	* tests/data/test-annotate/test21-pr19092.so.abi: Likewise.
	* tests/data/test-annotate/test22-pr19097-libstdc++.so.6.0.17.so.abi: Likewise.
	* tests/data/test-annotate/test3.so.abi: Likewise.
	* tests/data/test-annotate/test4.so.abi: Likewise.
	* tests/data/test-annotate/test5.o.abi: Likewise.
	* tests/data/test-annotate/test6.so.abi: Likewise.
	* tests/data/test-annotate/test7.so.abi: Likewise.
	* tests/data/test-annotate/test8-qualified-this-pointer.so.abi: Likewise.
	* tests/data/test-annotate/test9-pr18818-clang.so.abi: Likewise.
	* tests/test-annotate.cc: New test for ABIXML annotations.
	* tools/abidiff.cc: Add the new option '--no-corpus-path'.
	* tools/abidw.cc: Likewise. Also add the '--annotate' option.

reviews round 1

Signed-off-by: Dodji Seketeli <dodji@redhat.com>