Fix <https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-9169>.

Taken from this upstream commit, sans ChangeLog updates:
https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=583dd860d5b833037175247230a328f0050dbfe9

diff --git a/posix/regexec.c b/posix/regexec.c
index 91d5a797b8..084b1222d9 100644
--- a/posix/regexec.c
+++ b/posix/regexec.c
@@ -1293,8 +1293,10 @@ proceed_next_node (const re_match_context_t *mctx, Idx nregs, regmatch_t *regs,
 	      else if (naccepted)
 		{
 		  char *buf = (char *) re_string_get_buffer (&mctx->input);
-		  if (memcmp (buf + regs[subexp_idx].rm_so, buf + *pidx,
-			      naccepted) != 0)
+		  if (mctx->input.valid_len - *pidx < naccepted
+		      || (memcmp (buf + regs[subexp_idx].rm_so, buf + *pidx,
+				  naccepted)
+			  != 0))
 		    return -1;
 		}
 	    }
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<tr><td><span title='2022-03-16 15:48:52 +0100'>2022-03-16</span></td><td><a href='/guix/commit/gnu/packages/dunst.scm?id=f1aa1f3412169bf1eeee2f90adc426f766d79d3c'>gnu: dunst: Update to 1.8.1.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/dunst.scm (dunst): Update to 1.8.1.
* gnu/packages/patches/dunst-1.7.3-fix-crash.patch: Delete file.
* gnu/local.mk (dist_patch_DATA): Remove it.

Signed-off-by: Ludovic Courtès &lt;ludo@gnu.org&gt;
</span></span></td><td>Jai Vetrivelan</td></tr>
<tr><td><span title='2022-02-04 22:31:21 +0100'>2022-02-04</span></td><td><a href='/guix/commit/gnu/packages/dunst.scm?id=ba60aede97330c5145f3245eb67a70b984b59116'>gnu: dunst: Fix crash on invalid pixbuf notification.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/patches/dunst-1.7.3-fix-crash.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/dunst.scm (dunst)[source]&lt;#:patches&gt;: Add it.
</span></span></td><td>Danny Milosavljevic</td></tr>