IVGCVSW-4246 Clean build of backends with -Wextra

Change-Id: I9e8d5576b3ec04c871785d5f2f9545bf1136e59b
Signed-off-by: Derek Lamberti <derek.lamberti@arm.com>
diff --git a/src/backends/reference/workloads/ArgMinMax.cpp b/src/backends/reference/workloads/ArgMinMax.cpp
index 76616f1..db85b95 100644
--- a/src/backends/reference/workloads/ArgMinMax.cpp
+++ b/src/backends/reference/workloads/ArgMinMax.cpp
@@ -15,6 +15,8 @@
 void ArgMinMax(Decoder<float>& in, int32_t* out, const TensorInfo& inputTensorInfo,
                const TensorInfo& outputTensorInfo, ArgMinMaxFunction function, int axis)
 {
+    boost::ignore_unused(outputTensorInfo);
+
     unsigned int uAxis = armnnUtils::GetUnsignedAxis(inputTensorInfo.GetNumDimensions(), axis);
 
     const unsigned int outerElements = armnnUtils::GetNumElementsBetween(inputTensorInfo.GetShape(), 0, uAxis);
diff --git a/src/backends/reference/workloads/Dequantize.cpp b/src/backends/reference/workloads/Dequantize.cpp
index fafc03e..4025e8d 100644
--- a/src/backends/reference/workloads/Dequantize.cpp
+++ b/src/backends/reference/workloads/Dequantize.cpp
@@ -5,6 +5,7 @@
 
 #include "Dequantize.hpp"
 
+#include <boost/core/ignore_unused.hpp>
 namespace armnn
 {
 
@@ -13,6 +14,7 @@
                 const TensorInfo& inputInfo,
                 const TensorInfo& outputInfo)
 {
+    boost::ignore_unused(outputInfo);
     BOOST_ASSERT(inputInfo.GetNumElements() == outputInfo.GetNumElements());
     for (unsigned int i = 0; i < inputInfo.GetNumElements(); i++)
     {
diff --git a/src/backends/reference/workloads/DetectionPostProcess.cpp b/src/backends/reference/workloads/DetectionPostProcess.cpp
index d475dd8..3b384f1 100644
--- a/src/backends/reference/workloads/DetectionPostProcess.cpp
+++ b/src/backends/reference/workloads/DetectionPostProcess.cpp
@@ -155,6 +155,8 @@
                           float* detectionScores,
                           float* numDetections)
 {
+    boost::ignore_unused(anchorsInfo, detectionClassesInfo, detectionScoresInfo, numDetectionsInfo);
+
     // Transform center-size format which is (ycenter, xcenter, height, width) to box-corner format,
     // which represents the lower left corner and the upper right corner (ymin, xmin, ymax, xmax)
     std::vector<float> boxCorners(boxEncodingsInfo.GetNumElements());
diff --git a/src/backends/reference/workloads/Gather.cpp b/src/backends/reference/workloads/Gather.cpp
index c848a7c..5416855 100644
--- a/src/backends/reference/workloads/Gather.cpp
+++ b/src/backends/reference/workloads/Gather.cpp
@@ -9,6 +9,7 @@
 
 #include <backendsCommon/WorkloadData.hpp>
 
+#include <boost/core/ignore_unused.hpp>
 #include <boost/numeric/conversion/cast.hpp>
 
 namespace armnn
@@ -21,6 +22,7 @@
             const int32_t* indices,
             Encoder<float>& output)
 {
+    boost::ignore_unused(outputInfo);
     const TensorShape& paramsShape = paramsInfo.GetShape();
 
     unsigned int paramsProduct = 1;
diff --git a/src/backends/reference/workloads/Pooling2d.cpp b/src/backends/reference/workloads/Pooling2d.cpp
index ea8f4ee..8ff2eb4 100644
--- a/src/backends/reference/workloads/Pooling2d.cpp
+++ b/src/backends/reference/workloads/Pooling2d.cpp
@@ -84,7 +84,7 @@
         {
             case PoolingAlgorithm::Max:
             {
-                return [](float & accumulated, float kernelSize) {};
+                return [](float & /*accumulated*/, float /*kernelSize*/) {};
             }
 
             case PoolingAlgorithm::Average: