The custom mutex definition in Seq24 clashes with the mutex defined in gtkmm.
This patch renames the custom definition.

See https://bugs.launchpad.net/seq24/+bug/1647614 for upstream bug report.

diff --git a/src/midibus.h b/src/midibus.h
index 2cdf8e8..1bb02bd 100644
--- a/src/midibus.h
+++ b/src/midibus.h
@@ -90,7 +90,7 @@ class midibus
 
 
     /* locking */
-    mutex m_mutex;
+    seq24mutex m_mutex;
 
     /* mutex */
     void lock();
@@ -208,7 +208,7 @@ class mastermidibus
     sequence *m_seq;
 
     /* locking */
-    mutex m_mutex;
+    seq24mutex m_mutex;
 
     /* mutex */
     void lock();
diff --git a/src/midibus_portmidi.h b/src/midibus_portmidi.h
index 0119e9c..8c6a27a 100644
--- a/src/midibus_portmidi.h
+++ b/src/midibus_portmidi.h
@@ -65,7 +65,7 @@ class midibus
     long m_lasttick;
 
     /* locking */
-    mutex m_mutex;
+    seq24mutex m_mutex;
 
     /* mutex */
     void lock();
@@ -164,7 +164,7 @@ class mastermidibus
     sequence *m_seq;
 
     /* locking */
-    mutex m_mutex;
+    seq24mutex m_mutex;
 
     /* mutex */
     void lock();
diff --git a/src/mutex.cpp b/src/mutex.cpp
index b3f23fd..914114f 100644
--- a/src/mutex.cpp
+++ b/src/mutex.cpp
@@ -20,23 +20,23 @@
 
 #include "mutex.h"
 
-const pthread_mutex_t mutex::recmutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
+const pthread_mutex_t seq24mutex::recmutex = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
 const pthread_cond_t condition_var::cond  = PTHREAD_COND_INITIALIZER;
 
-mutex::mutex( )
+seq24mutex::seq24mutex( )
 {
     m_mutex_lock = recmutex;
 }
 
 void
-mutex::lock( )
+seq24mutex::lock( )
 {
     pthread_mutex_lock( &m_mutex_lock );
 }
 
 
 void
-mutex::unlock( )
+seq24mutex::unlock( )
 {
     pthread_mutex_unlock( &m_mutex_lock );
 }
diff --git a/src/mutex.h b/src/mutex.h
index 399f8a3..4f1b867 100644
--- a/src/mutex.h
+++ b/src/mutex.h
@@ -24,7 +24,7 @@
 
 #include <pthread.h>
 
-class mutex {
+class seq24mutex {
 
 private:
 
@@ -37,14 +37,14 @@ protected:
 
 public:
 
-    mutex();
+    seq24mutex();
 
     void lock();
     void unlock();
 
 };
 
-class condition_var : public mutex {
+class condition_var : public seq24mutex {
 
 private:
 
diff --git a/src/sequence.h b/src/sequence.h
index 2943946..9da8700 100644
--- a/src/sequence.h
+++ b/src/sequence.h
@@ -153,7 +153,7 @@ class sequence
     long m_rec_vol;
 
     /* locking */
-    mutex m_mutex;
+    seq24mutex m_mutex;
 
     /* used to idenfity which events are ours in the out queue */
     //unsigned char m_tag;
s='left'>Commit message (<a href='/guix/log/gnu/packages/compton.scm?id=5d77091cfc80b1f4b622ada760f54a3bae844e74&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-01-13 13:44:34 -0500'>2023-01-13</span></td><td><a href='/guix/commit/gnu/packages/compton.scm?id=0f85081ed1d99be57d3544e0307e7fa9ca043be9'>gnu: picom: Update to 10.2.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/compton.scm (picom): Update to 10.2.
[arguments]: Use a plain list and adjust accordingly.
[phases]{patch-autostart-files}: New phase.
</span></span></td><td>John Kehayias</td></tr>
<tr><td><span title='2022-02-15 15:01:30 +0100'>2022-02-15</span></td><td><a href='/guix/commit/gnu/packages/compton.scm?id=03533629a636fb7f92e26f1dea817f91d86f101d'>gnu: picom: Update to 9.1.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/compton.scm (picom): Update to 9.1.

Signed-off-by: Nicolas Goaziou &lt;mail@nicolasgoaziou.fr&gt;
</span></span></td><td>Jai Vetrivelan</td></tr>
<tr><td><span title='2022-02-07 23:47:23 +0100'>2022-02-07</span></td><td><a href='/guix/commit/gnu/packages/compton.scm?id=0abeec834df241b02fc9e9510b20ca5bf8d36fad'>gnu: picom: Update to 9.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/compton.scm (picom): Update to 9.

Signed-off-by: Marius Bakke &lt;marius@gnu.org&gt;
</span></span></td><td>Jai Vetrivelan</td></tr>
<tr><td><span title='2021-12-13 17:48:25 +0100'>2021-12-13</span></td><td><a href='/guix/commit/gnu/packages/compton.scm?id=8394619baceb118df92e355377fd543bb1aa501a'>gnu: Simplify package inputs.</a><span class='msg-avail'>...<span class='msg-tooltip'>This commit was obtained by running:

  ./pre-inst-env guix style

without any additional argument.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2021-02-16 16:37:39 +0800'>2021-02-16</span></td><td><a href='/guix/commit/gnu/packages/compton.scm?id=34f2a60875ceba552599b6e97e99e979571e64cb'>gnu: picom: Fix man pages generation.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/compton.scm (picom)[arguments]: Change flag 'build_docs' to
'with_docs'.

Signed-off-by: 宋文武 &lt;iyzsong@member.fsf.org&gt;
</span></span></td><td>Morgan Smith</td></tr>