From 6f80190aa0f94777ed9a9bb1bcaad6c6cba1385d Mon Sep 17 00:00:00 2001
From: John Rinehart <johnrichardrinehart@gmail.com>
Date: Mon, 7 Sep 2026 09:08:00 -0400
Subject: [PATCH] Honor caller-provided macOS deployment targets

Keep a nonempty CMAKE_OSX_DEPLOYMENT_TARGET supplied by a caller or
toolchain. Otherwise use MACOSX_DEPLOYMENT_TARGET from the environment,
falling back to the existing 10.15.4 default when neither supplies a value.

Mirror the selected target into the ordinary MACOSX_DEPLOYMENT_TARGET
variable so bundle metadata agrees with the compiler deployment target.
---
 buildscripts/cmake/SetupBuildEnvironment.cmake | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/buildscripts/cmake/SetupBuildEnvironment.cmake b/buildscripts/cmake/SetupBuildEnvironment.cmake
index 994b4ab30a..71a910bcfa 100644
--- a/buildscripts/cmake/SetupBuildEnvironment.cmake
+++ b/buildscripts/cmake/SetupBuildEnvironment.cmake
@@ -63,8 +63,14 @@ endif()
 
 # Mac-specific
 if(OS_IS_MAC)
-    set(MACOSX_DEPLOYMENT_TARGET 10.15.4)
-    set(CMAKE_OSX_DEPLOYMENT_TARGET 10.15.4)
+    if(NOT CMAKE_OSX_DEPLOYMENT_TARGET)
+        if(NOT "$ENV{MACOSX_DEPLOYMENT_TARGET}" STREQUAL "")
+            set(CMAKE_OSX_DEPLOYMENT_TARGET "$ENV{MACOSX_DEPLOYMENT_TARGET}")
+        else()
+            set(CMAKE_OSX_DEPLOYMENT_TARGET 10.15.4)
+        endif()
+    endif()
+    set(MACOSX_DEPLOYMENT_TARGET "${CMAKE_OSX_DEPLOYMENT_TARGET}")
 endif(OS_IS_MAC)
 
 # MSVC-specific