fix: set windows.h definitions on WIN32 instead of MSVC (#6534)

CHANGELOG.md

@@ -33,6 +33,7 @@
 - Dev: Fixed compilation warnings on clang-cl. (#6528)
 - Dev: Fixed compilation error in tests with Clang 21. (#6519)
 - Dev: The LuaLS meta files moved from `docs/plugin-meta.lua` to `docs/lua-meta/globals.lua`. (#6530)
+- Dev: Compile time definitions for `Windows.h` are now conditional based on `WIN32` instead of `MSVC`. (#6534)
 
 ## 2.5.4
 

src/CMakeLists.txt

@@ -1076,6 +1076,10 @@ target_compile_definitions(${LIBRARY_PROJECT} PUBLIC
     IRC_NAMESPACE=Communi
     $<$<BOOL:${WIN32}>:_WIN32_WINNT=0x0A00> # Windows 10
     $<$<BOOL:${BUILD_TESTS}>:CHATTERINO_WITH_TESTS>
+    # Disable min/max macros from Windows.h
+    $<$<BOOL:${WIN32}>:NOMINMAX>
+    # Exclude some headers when including Windows.h
+    $<$<BOOL:${WIN32}>:WIN32_LEAN_AND_MEAN>
     )
 
 set(_c2_qt_defs
@@ -1241,9 +1245,6 @@ if (MSVC)
             -Wno-missing-designated-field-initializers
         )
     endif()
-
-    # Disable min/max macros from Windows.h
-    target_compile_definitions(${LIBRARY_PROJECT} PUBLIC NOMINMAX)
 else ()
     target_compile_options(${LIBRARY_PROJECT} PUBLIC
         -Wall