From 7d718ada390bc54749fa35389437147e1bbefae1 Mon Sep 17 00:00:00 2001
From: Nadia Holmquist Pedersen <nadia@nhp.sh>
Date: Thu, 5 Dec 2024 15:38:44 +0100
Subject: [PATCH] cmake: set default CMAKE_OSX_DEPLOYMENT_TARGET before
 project()

project() appears to set it to an empty string (the value of nonexistent
$ENV{MACOSX_DEPLOYMENT_TARGET}?), causing our attempt to set its default
to fail. CMake bug?
---
 CMakeLists.txt | 3 +--
 flake.nix      | 6 ++++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c54b6450..531ca19f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,6 +9,7 @@ set(CMAKE_POLICY_DEFAULT_CMP0069 NEW)
 
 set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake" ${CMAKE_MODULE_PATH})
 set(CMAKE_USER_MAKE_RULES_OVERRIDE "${CMAKE_CURRENT_SOURCE_DIR}/cmake/DefaultBuildFlags.cmake")
+set(CMAKE_OSX_DEPLOYMENT_TARGET "10.15" CACHE STRING "Minimum OS X deployment version")
 
 option(USE_VCPKG "Use vcpkg for dependency packages" OFF)
 if (USE_VCPKG)
@@ -29,8 +30,6 @@ include(CheckIPOSupported)
 include(SetupCCache)
 include(Sanitizers)
 
-set(CMAKE_OSX_DEPLOYMENT_TARGET "10.15" CACHE STRING "Minimum OS X deployment version")
-
 set(CMAKE_C_STANDARD 11)
 set(CMAKE_C_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_STANDARD 17)
diff --git a/flake.nix b/flake.nix
index 7d17bb27..8dedde8f 100644
--- a/flake.nix
+++ b/flake.nix
@@ -95,7 +95,13 @@
             libtool
             ninja
             pkg-config
+            python3
           ];
+
+          # Undo the SDK setup done by nixpkgs so we can use AppleClang
+          shellHook = ''
+            unset DEVELOPER_DIR SDKROOT MACOSX_DEPLOYMENT_TARGET
+         '';
         };
       };
     }