Add -Wextra flag for Linux and macOS builds (#167)

Author: aobolensk

cmake/configure.cmake

@@ -21,8 +21,8 @@ set( CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin" )
 set( CMAKE_CXX_STANDARD 20 )
 
 if( UNIX )
-    set(CMAKE_C_FLAGS  "${CMAKE_C_FLAGS} -Wall -Wsign-compare -Werror")
-    set(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} -Wall -Wsign-compare -Werror")
+    set(CMAKE_C_FLAGS  "${CMAKE_C_FLAGS} -Wall -Wextra -Wno-unused-parameter -Wno-cast-function-type -Wsign-compare -Werror")
+    set(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wno-unused-parameter -Wno-cast-function-type -Wsign-compare -Werror")
     if (USE_COVERAGE)
         set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} --coverage")
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} --coverage")