diff --git a/CMakeLists.txt b/CMakeLists.txt
index a52ab4d093..592954bb6d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,6 +3,10 @@ cmake_minimum_required(VERSION 2.6)
 if (CMAKE_BINARY_DIR STREQUAL CMAKE_SOURCE_DIR)
     message(FATAL_ERROR "Building in-source is not supported! Create a build dir and remove ${CMAKE_SOURCE_DIR}/CMakeCache.txt")
 endif()
+
+include(CheckCCompilerFlag)
+include(CheckCXXCompilerFlag)
+
 set(ROOT_DIR "${CMAKE_CURRENT_LIST_DIR}")
 set(CMAKE_MACOSX_RPATH 1)
 
@@ -48,6 +52,50 @@ if (NOT OPENRCT2_COMMIT_SHA1_SHORT STREQUAL "HEAD")
     add_definitions(-DOPENRCT2_COMMIT_SHA1_SHORT="${OPENRCT2_COMMIT_SHA1_SHORT}")
 endif()
 
+function (ADD_CHECK_C_COMPILER_FLAG _CFLAGS _CACHE_VAR _FLAG)
+    CHECK_C_COMPILER_FLAG("${_FLAG}" "${_CACHE_VAR}")
+    if (${_CACHE_VAR})
+        set(${_CFLAGS} "${${_CFLAGS}} ${_FLAG}" PARENT_SCOPE)
+    else ()
+        message(STATUS "Unsupported CFLAG: ${_FLAG}")
+    endif ()
+endfunction ()
+
+function (ADD_CHECK_CXX_COMPILER_FLAG _CXXFLAGS _CACHE_VAR _FLAG)
+    CHECK_CXX_COMPILER_FLAG("${_FLAG}" "${_CACHE_VAR}")
+    if (${_CACHE_VAR})
+        set(${_CXXFLAGS} "${${_CXXFLAGS}} ${_FLAG}" PARENT_SCOPE)
+    else ()
+        message(STATUS "Unsupported CXXFLAG: ${_FLAG}")
+    endif ()
+endfunction ()
+
+# Launchpad turns on -Wdate-time for compilers that support it, this shouldn't break our build
+ADD_CHECK_C_COMPILER_FLAG(CMAKE_C_FLAGS C_WARN_WRITE_STRINGS -Wno-error=date-time)
+ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_WRITE_STRINGS -Wno-error=date-time)
+ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_NULL_DEREFERENCE -Wnull-dereference)
+ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_FINAL_TYPES -Wsuggest-final-types)
+ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_FINAL_METHODS -Wsuggest-final-methods)
+ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_OVERRIDE -Wsuggest-override)
+ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_DUPLICATED_COND -Wduplicated-cond)
+if (MINGW)
+    ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_OVERRIDE -Wno-error=redundant-decls)
+endif ()
+
+# Items below are not supported by ICC
+ADD_CHECK_C_COMPILER_FLAG(CMAKE_C_FLAGS C_WARN_REDUNDANT_DECLS -Wredundant-decls)
+ADD_CHECK_C_COMPILER_FLAG(CMAKE_C_FLAGS C_WARN_IGNORED_QUALIFIERS -Wignored-qualifiers)
+ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_REDUNDANT_DECLS -Wredundant-decls)
+ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_IGNORED_QUALIFIERS -Wignored-qualifiers)
+
+# -Wstrict-overflow is only active when -fstrict-overflow is enabled, but -fstrict-overflow
+# is enabled on -O2, -O3, -Os. This should help catch bugs locally before they reach Travis
+# As of 2a435bf -Wstrict-overflow=1 passes, but higher values do not.
+set(COMMON_COMPILE_OPTIONS "${COMMON_COMPILE_OPTIONS} -fstrict-overflow")
+ADD_CHECK_C_COMPILER_FLAG(CMAKE_C_FLAGS C_WARN_STRICT_OVERFLOW -Wstrict-overflow=1)
+ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_STRICT_OVERFLOW -Wstrict-overflow=1)
+
+
 # Include sub-projects
 include("${ROOT_DIR}/src/openrct2/CMakeLists.txt" NO_POLICY_SCOPE)
 include("${ROOT_DIR}/src/openrct2-cli/CMakeLists.txt" NO_POLICY_SCOPE)
diff --git a/src/openrct2/CMakeLists.txt b/src/openrct2/CMakeLists.txt
index 4a17e487a8..3b87b6fc7a 100644
--- a/src/openrct2/CMakeLists.txt
+++ b/src/openrct2/CMakeLists.txt
@@ -5,8 +5,6 @@ if (CMAKE_BINARY_DIR STREQUAL CMAKE_SOURCE_DIR)
 endif ()
 
 # CMake dependencies
-include(CheckCCompilerFlag)
-include(CheckCXXCompilerFlag)
 include(FindPkgConfig)
 
 # Options
@@ -255,49 +253,6 @@ set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu11 ${COMMON_COMPILE_OPTIONS} ${TARGE
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++14 ${COMMON_COMPILE_OPTIONS} ${TARGET_M}")
 set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${TARGET_M}")
 
-function (ADD_CHECK_C_COMPILER_FLAG _CFLAGS _CACHE_VAR _FLAG)
-    CHECK_C_COMPILER_FLAG("${_FLAG}" "${_CACHE_VAR}")
-    if (${_CACHE_VAR})
-        set(${_CFLAGS} "${${_CFLAGS}} ${_FLAG}" PARENT_SCOPE)
-    else ()
-        message(STATUS "Unsupported CFLAG: ${_FLAG}")
-    endif ()
-endfunction ()
-
-function (ADD_CHECK_CXX_COMPILER_FLAG _CXXFLAGS _CACHE_VAR _FLAG)
-    CHECK_CXX_COMPILER_FLAG("${_FLAG}" "${_CACHE_VAR}")
-    if (${_CACHE_VAR})
-        set(${_CXXFLAGS} "${${_CXXFLAGS}} ${_FLAG}" PARENT_SCOPE)
-    else ()
-        message(STATUS "Unsupported CXXFLAG: ${_FLAG}")
-    endif ()
-endfunction ()
-
-# Launchpad turns on -Wdate-time for compilers that support it, this shouldn't break our build
-ADD_CHECK_C_COMPILER_FLAG(CMAKE_C_FLAGS C_WARN_WRITE_STRINGS -Wno-error=date-time)
-ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_WRITE_STRINGS -Wno-error=date-time)
-ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_NULL_DEREFERENCE -Wnull-dereference)
-ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_FINAL_TYPES -Wsuggest-final-types)
-ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_FINAL_METHODS -Wsuggest-final-methods)
-ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_OVERRIDE -Wsuggest-override)
-ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_DUPLICATED_COND -Wduplicated-cond)
-if (MINGW)
-    ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_SUGGEST_OVERRIDE -Wno-error=redundant-decls)
-endif ()
-
-# Items below are not supported by ICC
-ADD_CHECK_C_COMPILER_FLAG(CMAKE_C_FLAGS C_WARN_REDUNDANT_DECLS -Wredundant-decls)
-ADD_CHECK_C_COMPILER_FLAG(CMAKE_C_FLAGS C_WARN_IGNORED_QUALIFIERS -Wignored-qualifiers)
-ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_REDUNDANT_DECLS -Wredundant-decls)
-ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_IGNORED_QUALIFIERS -Wignored-qualifiers)
-
-# -Wstrict-overflow is only active when -fstrict-overflow is enabled, but -fstrict-overflow
-# is enabled on -O2, -O3, -Os. This should help catch bugs locally before they reach Travis
-# As of 2a435bf -Wstrict-overflow=1 passes, but higher values do not.
-set(COMMON_COMPILE_OPTIONS "${COMMON_COMPILE_OPTIONS} -fstrict-overflow")
-ADD_CHECK_C_COMPILER_FLAG(CMAKE_C_FLAGS C_WARN_STRICT_OVERFLOW -Wstrict-overflow=1)
-ADD_CHECK_CXX_COMPILER_FLAG(CMAKE_CXX_FLAGS CXX_WARN_STRICT_OVERFLOW -Wstrict-overflow=1)
-
 # Defines
 if (USE_MMAP)
     add_definitions(-DUSE_MMAP)