463: Unanonymised QMutexLocker usage in OCIOIPNode.cpp (#476)

### Linked issues
Should fix
[#463](#463)

### Summarize your change.
Added "lock" variable name to all anonymous QMutexLocker instances to
extend their lifespan to the end of their scope. This matches the
QMutexLocker usage in other parts of the app (RVConsoleWindow.cpp and
QTAudioRenderer.cpp).

### Describe the reason for the change
Enabling OCIO was causing frequent crashing when reader threads were set
greater than 1, in particular under MacOS Sonoma.

Signed-off-by: kenmcgaugh <[email protected]>

Author: kenmcgaugh

src/lib/ip/OCIONodes/OCIOIPNode.cpp

@@ -294,7 +294,7 @@ OCIO::MatrixTransformRcPtr OCIOIPNode::getMatrixTransformXYZToRec709()
 {
     if (!m_matrix_xyz_to_rec709)
     {
-        QMutexLocker(&this->m_lock);
+        QMutexLocker lock(&this->m_lock);
         if (!m_matrix_xyz_to_rec709)
         {
             m_matrix_xyz_to_rec709 = createMatrixTransformXYZToRec709();
@@ -308,7 +308,7 @@ OCIO::MatrixTransformRcPtr OCIOIPNode::getMatrixTransformRec709ToXYZ()
 {
     if (!m_matrix_rec709_to_xyz)
     {
-        QMutexLocker(&this->m_lock);
+        QMutexLocker lock(&this->m_lock);
         if (!m_matrix_rec709_to_xyz)
         {
             m_matrix_rec709_to_xyz = createMatrixTransformXYZToRec709();
@@ -477,7 +477,7 @@ OCIOIPNode::evaluate(const Context& context)
 
             if (!m_transform)
             {
-                QMutexLocker(&this->m_lock);
+                QMutexLocker lock(&this->m_lock);
                 if (!m_transform)
                 {
                     m_transform = OCIO::GroupTransform::Create();
@@ -522,7 +522,7 @@ OCIOIPNode::evaluate(const Context& context)
 
             if (!m_transform)
             {
-                QMutexLocker(&this->m_lock);
+                QMutexLocker lock(&this->m_lock);
                 if (!m_transform)
                 {
                     m_transform = OCIO::GroupTransform::Create();
@@ -546,7 +546,7 @@ OCIOIPNode::evaluate(const Context& context)
         shaderName << "OCIO_sd_" << name() << "_" << hex << hashValue;
       }
 
-      QMutexLocker( &this->m_lock );
+      QMutexLocker lock(&this->m_lock);
       OCIO::GpuShaderDescRcPtr shaderDesc =
           OCIO::GpuShaderDesc::CreateShaderDesc();
       shaderDesc->setFunctionName( shaderName.str().c_str() );