From edf461865a7cbf2804f81a35bf2adfa838d52829 Mon Sep 17 00:00:00 2001
From: Sergey Fedorov <barracuda@macos-powerpc.org>
Date: Sun, 19 Jul 2026 13:20:47 +0000
Subject: [PATCH 25/71] fix(macos): control the frontend ObjC++ -std via a
 target flag, not COMPILE_OPTIONS

With the Portfile no longer forcing a global -std for ObjC++, CMake's global
CMAKE_OBJCXX_STANDARD=23 would otherwise apply to the frontend .mm files too.
Disable CMake's standard-flag injection for the contour target and pass the
frontend -std (default gnu++98) explicitly, guarded to the OBJCXX language. This
keeps the engine's coretext_locator.mm at C++23 while the frontend .mm files build
at gnu++98, and works with gcc-4.2 (which predates CMake's OBJCXX_STANDARD).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AeG2jwYMX5gdvvtUnx3PJa
---
 src/contour_macos/CMakeLists.txt | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/contour_macos/CMakeLists.txt b/src/contour_macos/CMakeLists.txt
index ebd82c59..bbee6339 100644
--- a/src/contour_macos/CMakeLists.txt
+++ b/src/contour_macos/CMakeLists.txt
@@ -80,10 +80,15 @@ if(APPLE)
     target_link_libraries(contour PRIVATE contour_macos)
     target_compile_options(contour PRIVATE ${_contour_macos_warn_opts})
 
-    # Force the ObjC++ standard explicitly (works even with gcc-4.2, which predates CMake's
-    # OBJCXX_STANDARD handling), and leave the target's plain C++ standard unset (no C++ TUs).
-    set_source_files_properties(${_app_sources} PROPERTIES
-        COMPILE_OPTIONS "-std=${CONTOUR_MACOS_OBJCXX_STD}")
+    # This target's .mm files build at a lower C++ standard than the C++23 engine. Turn off
+    # CMake's own standard-flag injection for the target (so it does not emit a competing
+    # -std from the global CMAKE_OBJCXX_STANDARD=23) and set the exact -std ourselves. Doing
+    # it via a flag rather than the OBJCXX_STANDARD property also works with gcc-4.2, which
+    # predates CMake's OBJCXX_STANDARD handling.
+    set_target_properties(contour PROPERTIES
+        OBJCXX_STANDARD ""
+        OBJCXX_STANDARD_REQUIRED OFF)
+    target_compile_options(contour PRIVATE $<$<COMPILE_LANGUAGE:OBJCXX>:-std=${CONTOUR_MACOS_OBJCXX_STD}>)
 
     # CoreGraphics is not a standalone linkable framework on 10.6 (like CoreText); its
     # symbols come via ApplicationServices. Link ApplicationServices, not CoreGraphics.