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.