diff --git a/development/scons/scons_manifest.py b/development/scons/scons_manifest.py
index e2d05e1053..cd163ad840 100644
--- a/development/scons/scons_manifest.py
+++ b/development/scons/scons_manifest.py
@@ -308,6 +308,7 @@ src_support_header_files = Split('''
     lyxalgo.h
     lyxlib.h
     lyxtime.h
+    mutex.h
     Messages.h
     numpunct_lyx_char_type.h
     os.h
@@ -348,6 +349,7 @@ src_support_files = Split('''
     lassert.cpp
     lstrings.cpp
     lyxtime.cpp
+    mutex.cpp
     Messages.cpp
     os.cpp
     Package.cpp
diff --git a/src/support/Makefile.am b/src/support/Makefile.am
index a6287330b4..9a8fccf61c 100644
--- a/src/support/Makefile.am
+++ b/src/support/Makefile.am
@@ -71,6 +71,8 @@ liblyxsupport_a_SOURCES = \
 	lyxlib.h \
 	lyxtime.cpp \
 	lyxtime.h \
+	mutex.h \
+	mutex.cpp \
 	Messages.cpp \
 	Messages.h \
 	numpunct_lyx_char_type.h \
diff --git a/src/support/unicode.cpp b/src/support/unicode.cpp
index dec1e9c0c6..b48f10609f 100644
--- a/src/support/unicode.cpp
+++ b/src/support/unicode.cpp
@@ -14,6 +14,7 @@
 
 #include "support/unicode.h"
 #include "support/debug.h"
+#include "support/mutex.h"
 
 #include <iconv.h>
 
@@ -25,7 +26,6 @@
 #include <ostream>
 #include <string>
 
-#include <QMutexLocker>
 
 using namespace std;
 
@@ -67,7 +67,7 @@ struct IconvProcessor::Impl
 	string tocode_;
 	string fromcode_;
 
-	QMutex mutex_; // iconv() is not thread save, see #7240
+	Mutex mutex_; // iconv() is not thread save, see #7240
 };
 
 
@@ -124,7 +124,7 @@ bool IconvProcessor::init()
 int IconvProcessor::convert(char const * buf, size_t buflen,
 		char * outbuf, size_t maxoutsize)
 {
-	QMutexLocker lock(&pimpl_->mutex_);
+	Mutex::Locker lock(&pimpl_->mutex_);
 
 	if (buflen == 0)
 		return 0;