diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7d726a5e22..8909de65d2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,16 +17,25 @@ if(NOT CMAKE_CONFIGURATION_TYPES)
     endif()
 endif()
 
+# https://blog.kitware.com/cmake-and-the-default-build-type/
+if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
+    set(default_build_type "Debug")
+    message(STATUS "Setting build type to '${default_build_type}' as none was specified.")
+    set(CMAKE_BUILD_TYPE "${default_build_type}" CACHE STRING "Choose the type of build." FORCE)
+    # Set the possible values of build type for cmake-gui
+    set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug" "Release")
+endif()
+
 if(APPLE AND NOT CMAKE_OSX_DEPLOYMENT_TARGET)
     # If no deployment target has been set default to the minimum supported
     # OS X version (this has to be set before the first project() call)
     set(CMAKE_OSX_DEPLOYMENT_TARGET 10.9 CACHE STRING "OS X Deployment Target")
 endif()
 
-project(wxWidgets)
-
 include(build/cmake/policies.cmake NO_POLICY_SCOPE)
 
+project(wxWidgets)
+
 # Initialize variables for quick access to wx root dir in sub dirs
 set(wxSOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 set(wxBINARY_DIR ${CMAKE_BINARY_DIR})
diff --git a/build/cmake/functions.cmake b/build/cmake/functions.cmake
index f5a613c7bf..13b861e20d 100644
--- a/build/cmake/functions.cmake
+++ b/build/cmake/functions.cmake
@@ -98,11 +98,15 @@ function(wx_set_common_target_properties target_name)
         ARCHIVE_OUTPUT_DIRECTORY "${wxOUTPUT_DIR}${wxPLATFORM_LIB_DIR}"
         RUNTIME_OUTPUT_DIRECTORY "${wxOUTPUT_DIR}${wxPLATFORM_LIB_DIR}"
         )
-    if(NOT wxCOMMON_TARGET_PROPS_DEFAULT_WARNINGS)
-        # Enable higher warnings for most compilers/IDEs
-        if(MSVC)
-            target_compile_options(${target_name} PRIVATE /W4)
+
+    if(MSVC)
+        if(wxCOMMON_TARGET_PROPS_DEFAULT_WARNINGS)
+            set(MSVC_WARNING_LEVEL "/W3")
+        else()
+            set(MSVC_WARNING_LEVEL "/W4")
         endif()
+        target_compile_options(${target_name} PRIVATE ${MSVC_WARNING_LEVEL})
+    else()
         # TODO: add warning flags for other compilers
     endif()
 
diff --git a/build/cmake/init.cmake b/build/cmake/init.cmake
index 5ad7bcdebd..576f8506e2 100644
--- a/build/cmake/init.cmake
+++ b/build/cmake/init.cmake
@@ -57,7 +57,12 @@ if(MSVC)
         wx_string_append(CMAKE_C_FLAGS " /MP")
         wx_string_append(CMAKE_CXX_FLAGS " /MP")
     endif()
-elseif(("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU") OR ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang"))
+
+    if(NOT POLICY CMP0092)
+        string(REGEX REPLACE "/W[0-4]" "" CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
+        string(REGEX REPLACE "/W[0-4]" "" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+    endif()
+elseif(("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU") OR ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang"))
     if(wxBUILD_OPTIMISE)
         set(GCC_PREFERRED_RELEASE_FLAGS " -O2 -fomit-frame-pointer")
         wx_string_append(CMAKE_CXX_FLAGS_RELEASE "${GCC_PREFERRED_RELEASE_FLAGS}")
@@ -95,8 +100,8 @@ endif()
 if(wxUSE_NO_RTTI)
     if(MSVC)
         add_compile_options("/GR-")
-    elseif(("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU") OR ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang"))
-        add_compile_options("-fno-rtti")
+    elseif(("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU") OR ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang"))
+        wx_string_append(CMAKE_CXX_FLAGS " -fno-rtti")
     endif()
     add_definitions("-DwxNO_RTTI")
 endif()
diff --git a/build/cmake/lib/stc/CMakeLists.txt b/build/cmake/lib/stc/CMakeLists.txt
index 25bb80801e..f96687d2d8 100644
--- a/build/cmake/lib/stc/CMakeLists.txt
+++ b/build/cmake/lib/stc/CMakeLists.txt
@@ -176,7 +176,7 @@ if(wxBUILD_PRECOMP)
     # standard c++ headers when using clang.
     # Do not disable precompiled headers entirely but use the main Scintilla
     # header as prefix header so there is at least a small speedup.
-    if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
+    if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
         set(wxSCINTILLA_PREC_HEADER "${wxSOURCE_DIR}/src/stc/scintilla/include/Scintilla.h")
     endif()
     wx_target_enable_precomp(wxscintilla ${wxSCINTILLA_PREC_HEADER})
diff --git a/build/cmake/options.cmake b/build/cmake/options.cmake
index 606ba6f75f..d86c47cc26 100644
--- a/build/cmake/options.cmake
+++ b/build/cmake/options.cmake
@@ -285,7 +285,7 @@ wx_option(wxUSE_COMBOCTRL "use wxComboCtrl class")
 wx_option(wxUSE_COMMANDLINKBUTTON "use wxCommmandLinkButton class")
 wx_option(wxUSE_DATAVIEWCTRL "use wxDataViewCtrl class")
 wx_option(wxUSE_DATEPICKCTRL "use wxDatePickerCtrl class")
-wx_option(wxUSE_DETECT_SM "_sm      use code to detect X11 session manager")
+wx_option(wxUSE_DETECT_SM "use code to detect X11 session manager" OFF)
 wx_option(wxUSE_DIRPICKERCTRL "use wxDirPickerCtrl class")
 wx_option(wxUSE_DISPLAY "use wxDisplay class")
 wx_option(wxUSE_EDITABLELISTBOX "use wxEditableListBox class")
diff --git a/build/cmake/policies.cmake b/build/cmake/policies.cmake
index 496aae7507..f68682df02 100644
--- a/build/cmake/policies.cmake
+++ b/build/cmake/policies.cmake
@@ -58,3 +58,8 @@ if(POLICY CMP0072)
     # FindOpenGL prefers GLVND by default when available.
     cmake_policy(SET CMP0072 NEW)
 endif()
+
+if(POLICY CMP0092)
+    # MSVC warning flags are not in CMAKE_<LANG>_FLAGS by default
+    cmake_policy(SET CMP0092 NEW)
+endif()