bug#56711: libunwind-julia fails to build on aarch64

[Akira Kyle]

I've been trying to get julia working on aarch64 but I was running 
into a linker error when guix was trying to build 
libunwind-julia. I tracked it down to the 
libunwind-julia-fix-GCC10-fno-common.patch not including a fix for 
aarch64 which is included in the upstream commit [1] which fixed 
this in libunwind 1.5.0. I gather libunwind-julia is at 1.3.1 due 
to julia 1.6.3 only building against that version, and checking 
the more recent julia versions, it seems julia is only updating 
it's dependency on libunwind to 1.5.0 with julia version 1.8.0 
which is only a release candidate at this point. So perhaps in the 
meantime, libunwind-julia-fix-GCC10-fno-common.patch could be 
easily updated so julia can start building on aarch64?

[1] 
https://github.com/libunwind/libunwind/commit/29e17d8d2ccbca07c423e3089a6d5ae8a1c9cb6e

Thanks!
Akira