Synchronize libiberty sources with gcc mainline.

Synchronize libiberty sources with gcc mainline.

	* libiberty: Sync with gcc.  Bring in:
	2019-08-08  Martin Liska  <mliska@suse.cz>

	PR bootstrap/91352
	* lrealpath.c (is_valid_fd): New function.

	2019-07-24  Martin Liska  <mliska@suse.cz>

	PR lto/91228
	* simple-object-elf.c (simple_object_elf_copy_lto_debug_sections):
	Find first '\0' starting from gnu_lto + 1.

	2019-07-12  Ren Kimura  <rkx1209dev@gmail.com>

	* simple-object-elf.c (simple_object_elf_match): Check zero value shstrndx.
	This fixes a Bug 90924.

	2019-07-22  Martin Liska  <mliska@suse.cz>

	* simple-object-elf.c (simple_object_elf_copy_lto_debug_sections):
	Do not search for gnu_lto_v1, but search for first '\0'.

	2019-07-18  Eduard-Mihai Burtescu  <eddyb@lyken.rs>

	* cplus-dem.c: Include rust-demangle.h.
	* rust-demangle.c: Include rust-demangle.h.
	* rust-demangle.h: New file.

	2019-05-31  Michael Forney  <mforney@mforney.org>

	* cp-demangle.c: Don't define CP_DYNAMIC_ARRAYS if __STDC_NO_VLA__
	is non-zero.

	2019-04-30  Ben L  <bobsayshilol@live.co.uk>

	* d-demangle.c (dlang_parse_assocarray): Correctly handle error result.
	* testsuite/d-demangle-expected: Add testcase.

	* d-demangle.c (dlang_parse_tuple): Correctly handle error result.
	* testsuite/d-demangle-expected: Add testcase.

	* d-demangle.c (dlang_parse_structlit): Correctly handle error result.
	* testsuite/d-demangle-expected: Add testcase.

	* d-demangle.c (dlang_parse_arrayliteral): Correctly handle error result.
	* testsuite/d-demangle-expected: Add testcase.

	* d-demangle.c (dlang_parse_integer): Fix stack underflow.
	* testsuite/d-demangle-expected: Add testcase.

	* cp-demangle (d_print_comp_inner): Guard against a NULL 'typed_name'.
	* testsuite/demangle-expected: Add testcase.

	* cp-demangle.c (d_encoding): Guard against NULL return values from
	d_right (dc).
	* testsuite/demangle-expected: Add testcase.

	2019-04-29  Ben L  <bobsayshilol@live.co.uk>

	* cp-demangle.c (d_expression_1): Don't peek ahead unless the current
	char is valid.
	* testsuite/demangle-expected: Add testcase.

	2019-04-10  Nick Clifton  <nickc@redhat.com>

	PR 89394
	* cp-demangle.c (cplus_demangle_fill_name): Reject negative
	lengths.
	(d_count_templates_scopes): Replace num_templates and num_scopes
	parameters with a struct d_print_info pointer parameter.  Adjust
	body of the function accordingly.  Add recursion counter and check
	that the recursion limit is not reached.
	(d_print_init): Pass dpi parameter to d_count_templates_scopes.
	Reset recursion counter afterwards, unless the recursion limit was
	reached.