Taken from upstream:
https://github.com/sigrokproject/pulseview/pull/39/commits/fb89dd11f2a4a08b73c498869789e38677181a8d.

From fb89dd11f2a4a08b73c498869789e38677181a8d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Stefan=20Br=C3=BCns?= <stefan.bruens@rwth-aachen.de>
Date: Wed, 28 Apr 2021 02:14:47 +0200
Subject: [PATCH] Fix broken build due to C++ template behind C linkage

glib/gatomic.h since 2.68 includes type_traits, which causes a compilation
error:
In file included from /usr/include/glib-2.0/glib/gatomic.h:31,
                 from /usr/include/glib-2.0/glib/gthread.h:32,
                 from /usr/include/glib-2.0/glib/gasyncqueue.h:32,
                 from /usr/include/glib-2.0/glib.h:32,
                 from /usr/include/libsigrokdecode/libsigrokdecode.h:25,
                 from /home/abuild/rpmbuild/BUILD/pulseview-0.4.2/pv/data/decode/annotation.cpp:21:
/usr/include/c++/10/type_traits:2308:3: error: template with C linkage
2308 |   template<typename _CTp, typename _Rp>

As libsigrokdecode.h declares extern C linkage itself where necessary,
remove it from pulseviews include statements from the last two occasions.
---
 pv/data/decode/annotation.cpp  | 2 --
 pv/views/trace/decodetrace.cpp | 2 --
 2 files changed, 4 deletions(-)

diff --git a/pv/data/decode/annotation.cpp b/pv/data/decode/annotation.cpp
index 7f233478..f8a5c47b 100644
--- a/pv/data/decode/annotation.cpp
+++ b/pv/data/decode/annotation.cpp
@@ -17,9 +17,7 @@
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
-extern "C" {
 #include <libsigrokdecode/libsigrokdecode.h>
-}
 
 #include <cassert>
 #include <vector>
diff --git a/pv/views/trace/decodetrace.cpp b/pv/views/trace/decodetrace.cpp
index 409f1d28..888064d0 100644
--- a/pv/views/trace/decodetrace.cpp
+++ b/pv/views/trace/decodetrace.cpp
@@ -17,9 +17,7 @@
  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
-extern "C" {
 #include <libsigrokdecode/libsigrokdecode.h>
-}
 
 #include <limits>
 #include <mutex>
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</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=361f2f647a0443bb769caee6288a03e990e4000c'>root</a>/<a href='/guix/log/gnu?id=361f2f647a0443bb769caee6288a03e990e4000c'>gnu</a>/<a href='/guix/log/gnu/installer?id=361f2f647a0443bb769caee6288a03e990e4000c'>installer</a>/<a href='/guix/log/gnu/installer/substitutes.scm?id=361f2f647a0443bb769caee6288a03e990e4000c'>substitutes.scm</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/gnu/installer/substitutes.scm?id=361f2f647a0443bb769caee6288a03e990e4000c&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-12-11 21:37:07 +0100'>2020-12-11</span></td><td><a href='/guix/commit/gnu/installer/substitutes.scm?id=8361817bf693742757b096468198626f297bb09e'>install: Discover local substitute servers.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/installer/substitutes.scm: New file.
* gnu/installer/newt/substitutes.scm: New file.
* gnu/local.mk (INSTALLER_MODULES): Add them.
* po/guix/POTFILES.in: Add gnu/installer/newt/substitutes.scm.
* gnu/installer/proxy.scm (with-silent-shepherd): Move to ...
* gnu/installer/utils.scm: ... here.
* gnu/installer/record.scm (&lt;installer&gt;)[substitutes-page]: New field.
* gnu/installer/newt.scm (substitutes-page): New procedure,
(newt-installer): register it.
* gnu/installer.scm (installer-steps): Add "substitutes-page" step.
* gnu/system/install.scm (%installation-services): Add avahi-service-type and
enable substitute server discover in guix-service-type.
[&lt;name-service-switch&gt;]: Set it to %mdns-host-lookup-nss.
</span></span></td><td>Mathieu Othacehe</td></tr>