bug#38632: 27.0.50; Emacs process name is changed permanently upon creating a named thread

[Eli Zaretskii]

> From: Glenn Morris <rgm@gnu.org>
> Cc: mattiase@acm.org,  38632@debbugs.gnu.org,  rpluim@gmail.com
> Date: Wed, 08 Jan 2020 14:34:48 -0500
> 
> Now a different problem:
> 
> thread.o: In function `run_thread':
> /build/1rjrmrn0sv17hak6ql2igch5f221shf2-source/src/thread.c:729:
> undefined reference to `sys_thread_set_name'

Fixed.