Sync libiberty sources with gcc master versions.

Sync libiberty sources with gcc master versions.

.	* libiberty: Sync with gcc.  Bring in:
	2019-01-09  Sandra Loosemore  <sandra@codesourcery.com>

	PR other/16615

	* cp-demangle.c: Mechanically replace "can not" with "cannot".
	* floatformat.c: Likewise.
	* strerror.c: Likewise.

	2018-12-22  Jason Merrill  <jason@redhat.com>

	Remove support for demangling GCC 2.x era mangling schemes.
	* cplus-dem.c: Remove cplus_mangle_opname, cplus_demangle_opname,
	internal_cplus_demangle, and all subroutines.
	(libiberty_demanglers): Remove entries for ancient GNU (pre-3.0),
	Lucid, ARM, HP, and EDG demangling styles.
	(cplus_demangle): Remove 'work' variable.  Don't call
	internal_cplus_demangle.

include	* Merge from GCC:
	2018-12-22  Jason Merrill  <jason@redhat.com>

	* demangle.h: Remove support for ancient GNU (pre-3.0), Lucid,
	ARM, HP, and EDG demangling styles.