build: update gnulib submodule to latest

This pulls in the latest regex module from gnulib, including a fix
to make it honor the RE_NO_EMPTY_RANGES syntax bit.

tests: temporarily disable irrelevant-to-grep failing C++ fcntl-h-tests
* bootstrap.conf (gnulib_tool_option_extras): Temporarily add
--avoid=fcntl-h-tests, until the C++ part of that test is fixed.

1 files changed, 0 insertions, 0 deletions

diff --git a/gnulib b/gnulib
-Subproject aadf332a5c5f209affd38c35b4e9faaa8a0adec
+Subproject 602e3e6b709592f883ebb7bf58df1f955ea4b8f