Merge branch 'ci-utf8'

Fix UTF-8 build under MSW and improve its coverage in the CI jobs.

See #23313.

Closes #23328.

appveyor.yml

@@ -34,6 +34,11 @@ environment:
     ARCH: x64
     wxUSE_STL: 1
     APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
+  - TOOLSET: msbuild
+    CONFIGURATION: Debug
+    ARCH: x64
+    wxUSE_UNICODE_UTF8: 1
+    APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2022
   - TOOLSET: nmake
     VS: '14.0'
     BUILD: debug
@@ -67,11 +72,13 @@ before_build:
 - ps: |
     $env:PATH = $env:PATH -replace "C:\\Program Files\\Git\\usr\\bin",""
     if (-not (Test-Path env:wxUSE_STL)) { $env:wxUSE_STL = '0' }
+    if (-not (Test-Path env:wxUSE_UNICODE_UTF8)) { $env:wxUSE_UNICODE_UTF8 = '0' }
     if (-not (Test-Path env:wxUSE_WEBVIEW_EDGE)) { $env:wxUSE_WEBVIEW_EDGE = '0' }
     if (($env:TOOLSET -ne "msys2") -and ($env:TOOLSET -ne "cygwin")) {
       $txt = gc include\wx\msw\setup.h
       Write-Output $txt |
       %{$_ -replace "define wxUSE_STL 0", "define wxUSE_STL $env:wxUSE_STL"} |
+      %{$_ -replace "define wxUSE_UNICODE_UTF8 0", "define wxUSE_UNICODE_UTF8 $env:wxUSE_UNICODE_UTF8"} |
       %{$_ -replace "define wxUSE_WEBVIEW_EDGE 0", "define wxUSE_WEBVIEW_EDGE $env:wxUSE_WEBVIEW_EDGE"} |
       sc include\wx\msw\setup.h
     }