Bug#1073254: geary: please add support for loong64

[wuruilong]

Source: geary
Version: 46.0-3
Followup-For: Bug #1073254
X-Debbugs-Cc: wuruilong at loongson.cn

Dear Maintainer,

- Sorry, indeed.
- libunwind will soon support loongarch, refer to https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1051757
- The attached patch does compile successfully in version 46.0-2, but there is a new problem after upgrading the version
I will continue to work on the compilation failure and will submit the attached patch when it is resolved.

wuruilong