Why is my Vim build failing on WSL?

Question

I'm running Ubuntu 20.04.4 under WSL2 on Windows 11. I've cloned https://github.com/vim/vim.git in the environment. (The latest commit is tagged as v9.0.0260.) When I go to the directory and do this ...

./configure
sudo make

... the latter command reports:

/usr/bin/ld: objects/os_unix.o: in function `stop_timeout':
/home/me/git/vim/src/os_unix.c:8281: undefined reference to `timer_settime'
/usr/bin/ld: objects/os_unix.o: in function `start_timeout':
/home/me/git/vim/src/os_unix.c:8321: undefined reference to `timer_create'
/usr/bin/ld: /home/me/git/vim/src/os_unix.c:8334: undefined reference to `timer_settime'
/usr/bin/ld: objects/os_unix.o: in function `delete_timer':
/home/me/git/vim/src/os_unix.c:8349: undefined reference to `timer_delete'

A bit of searching shows that the problem might be related to the need for a -lrt flag somewhere in the build, to include the timer library. But I'm at a loss as to what changes the makefiles would need. The ./configure command doesn't tell me that I'm missing anything. Is there something I can do about it?

Answer 1

At github.com/vim/vim/issues/10831 is this comment:

"Generally, after syncing to head, make distclean might be needed, because the configure checks may need to run again for changes in configure or build environment."

I ran: make distclean, after which the usual sequence of build instructions worked.

Thanks to @Matt for the insight.