In the newer GCC version, C globals are now not defined in the "common" bss section by default. linunwind will fail to build because of multiple definitions of _U_dyn_info_list symbol. This can be fixed by either putting an extern in front of the extra defs, save a single location, or using the -fcommon option to preserve the older GCC behavior.

Suggesting using the -fcommon option for the libunwind build as that will be safer, and we wont need to modify third party vendor-ed code.

More info can be found here: https://gcc.gnu.org/gcc-10/porting_to.html