Taken from upstream: https://github.com/open-source-parsers/jsoncpp/issues/1235.

From ac2870298ed5b5a96a688d9df07461b31f83e906 Mon Sep 17 00:00:00 2001
From: Derick Vigne <derickvigne@me.com>
Date: Tue, 26 Jan 2021 14:59:12 -0500
Subject: [PATCH] Fixed pkg-config Version

---
 pkg-config/jsoncpp.pc.in | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkg-config/jsoncpp.pc.in b/pkg-config/jsoncpp.pc.in
index 632a377f5..2a2221069 100644
--- a/pkg-config/jsoncpp.pc.in
+++ b/pkg-config/jsoncpp.pc.in
@@ -5,7 +5,7 @@ includedir=@includedir_for_pc_file@
 
 Name: jsoncpp
 Description: A C++ library for interacting with JSON
-Version: @JSONCPP_VERSION@
+Version: @PROJECT_VERSION@
 URL: https://github.com/open-source-parsers/jsoncpp
 Libs: -L${libdir} -ljsoncpp
 Cflags: -I${includedir}
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<div class='path'>path: <a href='/guix/log/?id=a916d50566e77ae730e34f1753ceb78cc6bf0a5a'>root</a>/<a href='/guix/log/HACKING?id=a916d50566e77ae730e34f1753ceb78cc6bf0a5a'>HACKING</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/HACKING?id=a916d50566e77ae730e34f1753ceb78cc6bf0a5a&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-10-23 12:57:20 -0400'>2020-10-23</span></td><td><a href='/guix/commit/HACKING?id=73faee9fb25465f1b236f5f94e1052145655736f'>doc: Fix typo in HACKING.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Contributing): s/informations/information/.
</span></span></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2020-01-09 23:33:04 +0100'>2020-01-09</span></td><td><a href='/guix/commit/HACKING?id=2d315cd428484537e763d7f7c676dc5fff7995f6'>doc: Move "Commit Access" section from 'HACKING' to the manual.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Commit Access): Remove.
(Contributing): Update URL of the manual.
* doc/contributing.texi (Commit Access): New section.
(Submitting Patches): Add cross reference.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-01-09 23:33:04 +0100'>2020-01-09</span></td><td><a href='/guix/commit/HACKING?id=a7bde77d247ed0765f5378779d67b4668c5d7648'>doc: Add "Tracking Bugs and Patches" section.</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/contributing.texi (Tracking Bugs and Patches): New section.
(Submitting Patches): Refer to it.
* doc/guix.texi: Update copyright line.
* HACKING (Using emacs-debbugs): Remove.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-07-13 14:25:19 -0400'>2019-07-13</span></td><td><a href='/guix/commit/HACKING?id=06e1ecbf17fee7fe513ad2808d8175fb3565ae3e'>doc: Update keyserver URL.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Commit Access): Change keyserver URL to 'keys.openpgp.org'.
</span></span></td><td>Leo Famulari</td></tr>
<tr><td><span title='2019-02-11 23:23:27 +0100'>2019-02-11</span></td><td><a href='/guix/commit/HACKING?id=6701edbfad62ba9572ffd35497df3db27b208ba5'>HACKING: Update key server.</a><span class='msg-avail'>...<span class='msg-tooltip'>* HACKING (Commit Access): Recommend pool.sks-keyservers.net.
</span></span></td><td>Ludovic Courtès</td></tr>