Update from Gnulib

This incorporates:
2019-04-07 Add copyright notices in several files
* build-aux/config.sub, doc/misc/texinfo.tex, lib/_Noreturn.h:
Copy from Gnulib.
* lib/gnulib.mk.in: Regenerate.
1 job for master in 39 minutes and 35 seconds
Status Job ID Name Coverage
  Test
failed #1347
test-all

00:39:35

 
Name Stage Failure
failed
test-all Test
Makefile:313: recipe for target 'check-doit' failed
make[2]: Leaving directory '/builds/emacs/emacs/test'
Makefile:288: recipe for target 'check-expensive' failed
make[1]: Leaving directory '/builds/emacs/emacs/test'
make[2]: *** [check-doit] Error 1
make[1]: *** [check-expensive] Error 2
Makefile:962: recipe for target 'check-expensive' failed
make: *** [check-expensive] Error 2
ERROR: Job failed: exit code 1