gcc14 doesn’t build for x86_64 on macOS 15 (Xcode 16): “Undefined symbols for architecture x86_64” while linking libgcc_s.1.dylib

[markmentovai (Mark Mentovai)]

Forked from #70641.

:info:build Undefined symbols for architecture x86_64:
:info:build   "___deregister_frame_info", referenced from:
:info:build      -reexported_symbols_list command line option
:info:build   "___deregister_frame_info_bases", referenced from:
:info:build      -reexported_symbols_list command line option
:info:build   "___register_frame_info", referenced from:
:info:build      -reexported_symbols_list command line option
:info:build   "___register_frame_info_bases", referenced from:
:info:build      -reexported_symbols_list command line option
:info:build   "___register_frame_info_table", referenced from:
:info:build      -reexported_symbols_list command line option
:info:build   "___register_frame_info_table_bases", referenced from:
:info:build      -reexported_symbols_list command line option
:info:build   "___register_frame_table", referenced from:
:info:build      -reexported_symbols_list command line option
:info:build ld: symbol(s) not found for architecture x86_64
:info:build collect2: error: ld returned 1 exit status
:info:build make[3]: *** [libgcc_s.1.dylib] Error 1

In particular, see comment:ticket:70641:39 and comment:ticket:70641:45 for an explanation of why this is happening in macOS 15, and why it’s x86_64-specific. This bug will also affect macOS 14 with Xcode 16, as that build configuration uses the macOS 15 SDK.

This is on file upstream at ​https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116809.