bug#34608: date +%+4C is unimplemented, contrary to POSIX

[Paul Eggert]

Eric Blake wrote:

> The best I can do is search austingroupbugs.net for all bugs containing
> strftime, which pulls up a current total of 25 issues.

Thanks for doing that. I read through those issues, and the only one that seems 
relevant (i.e., resolved by austingroup but not in Gnulib) is the business with 
the + conversion specification flag. I installed this Gnulib patch to implement 
the flag:

https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=188d87b05190690d6f8b0577ec65ef221a711d08

Then I installed the attached coreutils patches to propagate the Gnulib patch 
into coreutils, and I am marking this coreutils bug as done.

glibc strftime should also support the + conversion specification flag. I filed 
a bug report for that here:

https://sourceware.org/bugzilla/show_bug.cgi?id=24264

0001-build-update-gnulib-submodule-to-latest.patch
Description: Text Data

0002-date-conversion-specification-flag.patch
Description: Text Data

0003-doc-fix-typo-in-previous-patch.patch
Description: Text Data