IVGCVSW-4246 Enable -Wextra by default

!referencetests:218340

Change-Id: If24a604310d0363b1f09b406e4d53ebfeb106aad
Signed-off-by: Derek Lamberti <derek.lamberti@arm.com>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d0f3d7a..d268983 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -133,7 +133,7 @@
         )
     # The generated tensorflow protobuf .cc files are not warning clean and we can't fix them.
     if(COMPILER_IS_GNU_LIKE)
-        set_source_files_properties(${TF_PROTOBUFS} PROPERTIES COMPILE_FLAGS "-Wno-conversion -Wno-sign-conversion")
+        set_source_files_properties(${TF_PROTOBUFS} PROPERTIES COMPILE_FLAGS "-Wno-unused-variable -Wno-unused-parameter -Wno-conversion -Wno-sign-conversion")
     endif()
 
     add_library_ex(armnnTfParser SHARED ${armnn_tf_parser_sources})