Suppress a warning from grep which causes tests to fail.

Taken from upstream pull request:

  https://github.com/aureliojargas/clitest/pull/54

diff --git a/test/inline-match-egrep.sh b/test/inline-match-egrep.sh
--- a/test/inline-match-egrep.sh
+++ b/test/inline-match-egrep.sh
@@ -42,7 +42,7 @@ $ printf ' \t  \t\t   \n'       #=> --egrep ^ 	  		   $
 # egrep regexes. You'll need to test in your system if that's the
 # case. I recommend using a literal tab to avoid problems.
 
-$ printf 'may\tfail'            #=> --egrep ^may\tfail$
+$ printf 'may\tfail'            #=> --egrep ^may\\tfail$
 $ printf 'may\tfail'            #=> --egrep ^may[\t]fail$
 $ printf 'will\tmatch'          #=> --egrep ^will	match$
 
@@ -51,7 +51,7 @@ $ printf 'will\tmatch'          #=> --egrep ^will	match$
 # These tests will fail:
 
 $ printf 'will\nfail'           #=> --egrep will.*fail
-$ printf 'will\nfail'           #=> --egrep will\nfail
+$ printf 'will\nfail'           #=> --egrep will\\nfail
 
 # If one line of a multiline results matches, the test is OK
 
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<tr><td><span title='2024-09-08 02:00:00 +0200'>2024-09-08</span></td><td><a href='/guix/commit/gnu/packages/boost.scm?id=7efce3966293f833be9a0bb24e3c5571a6033900'>gnu: boost-signals2: Use G-expressions.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/boost.scm (boost-signals2)[arguments]:
Rewrite as G-expressions.

Change-Id: I83c05f97089cae8a14fedf52c34e898addfb5701
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2024-09-08 02:00:00 +0200'>2024-09-08</span></td><td><a href='/guix/commit/gnu/packages/boost.scm?id=6ab1a5bf5178f49612eb19ab1dbae9223b6c9da1'>gnu: boost-signals2: Update to 1.83.0-0.2ecf1b5.</a><span class='msg-avail'>...<span class='msg-tooltip'>This ‘fixes’ the build as our hash no longer matched upstream's Git tag.

* gnu/packages/boost.scm (boost-signals2): Update to 1.83.0-0.2ecf1b5.

Change-Id: I1e0849ac71bcba22c8b367601107caf58b51a434
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2024-08-31 10:45:43 +0200'>2024-08-31</span></td><td><a href='/guix/commit/gnu/packages/boost.scm?id=8a20f58420ff62cf2e9daeaf88d8ec1dfecb81b4'>gnu: Boost: Fix a bug that breaks libetonyek.</a><span class='msg-avail'>...<span class='msg-tooltip'>This fixes &lt;https://issues.guix.gnu.org/72040&gt;.

* gnu/packages/patches/boost-fix-duplicate-definitions-bug.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/boost.scm (boost)[source]: Use it.
(boost-for-source-highlight): New variable, not using the patch.
* gnu/packages/pretty-print.scm (source-highlight)[inputs]: Replace BOOST with
BOOST-FOR-SOURCE-HIGHLIGHT.

Change-Id: I5fbc9eb5000aefd7d3a14cc7a0482741032b5400
</span></span></td><td>Leo Famulari</td></tr>
<tr><td><span title='2024-08-31 10:44:30 +0200'>2024-08-31</span></td><td><a href='/guix/commit/gnu/packages/boost.scm?id=f40553702db7f633f4966ae29655c32ee224cd53'>gnu: boost: Update to 1.83.0.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/boost.scm (boost): Update to 1.83.0.
[source](patches): Add new and remove old upstream patches.
(patch-flags): Strip prefix to match source directory structure.

Signed-off-by: Maxim Cournoyer &lt;maxim.cournoyer@gmail.com&gt;
Change-Id: I68d0d50ea916c938d4b30e8e074202a9380cfa0b
</span></span></td><td>Greg Hogan</td></tr>
<tr><td><span title='2024-08-31 10:42:17 +0200'>2024-08-31</span></td><td><a href='/guix/commit/gnu/packages/boost.scm?id=d23f7b77d7a8609ae6572691aed139208f9c174b'>gnu: boost: Import the correct set of modules.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/boost.scm (boost) [arguments] &lt;modules&gt;: Replace
%default-gnu-imported-modules with %default-gnu-modules.

Change-Id: Idb491a2b7cae3a52783a2c92b78b362de0adf49e
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2024-08-31 10:42:16 +0200'>2024-08-31</span></td><td><a href='/guix/commit/gnu/packages/boost.scm?id=f59df1aa3c104aabff3291f6b8b155fb01aebc06'>build-systems: gnu: Export %default-gnu-imported-modules and %default-gnu-mod...</a><span class='msg-avail'>...<span class='msg-tooltip'>Until now users would have to cargo cult or inspect the private
%default-modules variable of (guix build-systems gnu) to discover which
modules to include when extending the used modules via the #:modules argument.

The renaming was automated via the command:

  $ git grep -l %gnu-build-system-modules
    | xargs sed 's/%gnu-build-system-modules/%default-gnu-imported-modules/' -i

* guix/build-system/gnu.scm (%gnu-build-system-modules): Rename to...
(%default-gnu-imported-modules): ... this.
(%default-modules): Rename to...
(%default-gnu-modules): ... this.  Export.
(dist-package, gnu-build, gnu-cross-build): Adjust accordingly.

Change-Id: Idef307fff13cb76f3182d782b26e1cd3a5c757ee
</span></span></td><td>Maxim Cournoyer</td></tr>