diff --git a/CMakeLists.txt b/CMakeLists.txt
index 49a45e73fb..05b014e95d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -114,7 +114,7 @@ option(USE_MMAP "Use mmap to try loading rct2's data segment into memory.")
 option(WITH_TESTS "Build tests")
 option(DISABLE_TTF "Disable support for TTF provided by SDL2_ttf.")
 
-set(COMMON_COMPILE_OPTIONS "${COMMON_COMPILE_OPTIONS} -fstrict-aliasing -Werror -Wundef -Wmissing-declarations -Winit-self -Wall -Wno-unknown-pragmas -Wno-unused-function -Wno-missing-braces -Wno-comment")
+set(COMMON_COMPILE_OPTIONS "${COMMON_COMPILE_OPTIONS} -fstrict-aliasing -Werror -Wundef -Wmissing-declarations -Winit-self -Wall -Wno-unknown-pragmas -Wno-unused-function -Wno-missing-braces -Wno-comment -Wshadow  -Wmissing-declarations -Wredundant-decls")
 
 # On mingw all code is already PIC, this will avoid compiler error on redefining this option
 if(NOT MINGW)
@@ -262,7 +262,7 @@ else ()
 endif ()
 
 # set necessary flags to compile code as is
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${TARGET_M} -std=gnu99 ${COMMON_COMPILE_OPTIONS} -Wimplicit -Wshadow")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${TARGET_M} -std=gnu99 ${COMMON_COMPILE_OPTIONS} -Wimplicit")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${TARGET_M} -std=gnu++11 ${COMMON_COMPILE_OPTIONS} -Wnon-virtual-dtor")
 set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${TARGET_M}")
 set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${CMAKE_SHARED_LINKER_FLAGS} ${PIE_FLAG}")