diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 0323603fc..f9ec419e9 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -693,14 +693,13 @@ if(MSVC)
 	endif()
 else()
 	# GCC or compatible compilers such as Clang
+	set(WARNING_FLAGS "-Wall -Wextra")
+	set(WARNING_FLAGS "${WARNING_FLAGS} -Wno-unused-parameter -Wno-implicit-fallthrough")
 	if(WARN_ALL)
-		set(RELEASE_WARNING_FLAGS "-Wall")
+		set(RELEASE_WARNING_FLAGS "${WARNING_FLAGS}")
 	else()
 		set(RELEASE_WARNING_FLAGS "")
 	endif()
-	if(CMAKE_CXX_COMPILER_ID MATCHES "(Apple)?Clang")
-		set(WARNING_FLAGS "${WARNING_FLAGS} -Wsign-compare")
-	endif()
 
 	if(APPLE AND USE_LUAJIT)
 		# required per http://luajit.org/install.html
@@ -742,7 +741,7 @@ else()
 		endif()
 	endif()
 
-	set(CMAKE_CXX_FLAGS_RELEASE "-DNDEBUG ${RELEASE_WARNING_FLAGS} ${WARNING_FLAGS} ${OTHER_FLAGS} -Wall -pipe -funroll-loops")
+	set(CMAKE_CXX_FLAGS_RELEASE "-DNDEBUG ${RELEASE_WARNING_FLAGS} ${OTHER_FLAGS} -pipe -funroll-loops")
 	if(CMAKE_SYSTEM_NAME MATCHES "(Darwin|BSD|DragonFly)")
 		set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -Os")
 	else()
@@ -755,8 +754,9 @@ else()
 			set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} ${MATH_FLAGS}")
 		endif()
 	endif()
-	set(CMAKE_CXX_FLAGS_SEMIDEBUG "-g -O1 -Wall ${WARNING_FLAGS} ${OTHER_FLAGS}")
-	set(CMAKE_CXX_FLAGS_DEBUG "-g -O0 -Wall ${WARNING_FLAGS} ${OTHER_FLAGS}")
+	set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELEASE} -g")
+	set(CMAKE_CXX_FLAGS_SEMIDEBUG "-g -O1 ${WARNING_FLAGS} ${OTHER_FLAGS}")
+	set(CMAKE_CXX_FLAGS_DEBUG "-g -O0 ${WARNING_FLAGS} ${OTHER_FLAGS}")
 
 	if(USE_GPROF)
 		set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -pg")