gcc PR lto/47247
* plugin.cc (get_symbols_v2): New function.
(Plugin::load): Add LDPT_GET_SYMBOLS_V2.
(is_referenced_from_outside): New function.
(Pluginobj::get_symbol_resolution_info): Add version parameter, return
LDPR_PREVAILING_DEF_IRONLY_EXP when using new version.
(get_symbols): Pass version parameter.
(get_symbols_v2): New function.
* plugin.h (Pluginobj::get_symbol_resolution_info): Add version
parameter.
* testsuite/plugin_test.c (get_symbols_v2): New static variable.
(onload): Add LDPT_GET_SYMBOLS_V2.
(all_symbols_read_hook): Use get_symbols_v2; check for
LDPR_PREVAILING_DEF_IRONLY_EXP.
* testsuite/plugin_test_3.sh: Update expected results.