> This is still a glibc bug, not a grep bug; it's just that we don't have a fix.
I finally got around to finding the correct glibc bug report for this grep bug. Here it is: https://sourceware.org/bugzilla/show_bug.cgi?id=11053 I added a comment to the glibc bug, saying that it causes grep Bug#22793 <https://bugs.gnu.org/22793>. Paolo Bonzini reported the glibc bug in 2009 and is the current assignee. I think he's pretty busy doing other things. It'd be nice if someone could fix the glibc bug (or at least, fix it in Gnulib), though I suspect that any fix will not be trivial.
