From 60b0a1fde2a9a48035cf2a29e3decae29ecd285b Mon Sep 17 00:00:00 2001
From: Maarten Bent <MaartenBent@users.noreply.github.com>
Date: Wed, 17 Jul 2019 01:12:33 +0200
Subject: [PATCH] CMake: Fix MSVC warning when using NMake

Fix warning: Command line warning D9025 : overriding '/W3' with '/W4'
Remove /W3, either via a regex or via new policy CMP0092 (CMake 3.15).

The policy has to be set before calling project(), otherwise the
CMAKE_<LANG>_FLAGS are already initialized.

See https://trac.wxwidgets.org/ticket/18438
---
 CMakeLists.txt              |  4 ++--
 build/cmake/functions.cmake | 12 ++++++++----
 build/cmake/init.cmake      |  5 +++++
 build/cmake/policies.cmake  |  5 +++++
 4 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7d726a5e22..fe69cf3a9d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -23,10 +23,10 @@ if(APPLE AND NOT CMAKE_OSX_DEPLOYMENT_TARGET)
     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 703d0c3417..944db20ecd 100644
--- a/build/cmake/init.cmake
+++ b/build/cmake/init.cmake
@@ -57,6 +57,11 @@ if(MSVC)
         wx_string_append(CMAKE_C_FLAGS " /MP")
         wx_string_append(CMAKE_CXX_FLAGS " /MP")
     endif()
+
+    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}" STREQUAL "Clang"))
     if(wxBUILD_OPTIMISE)
         set(GCC_PREFERRED_RELEASE_FLAGS " -O2 -fomit-frame-pointer")
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()