From a862e32a61e7f3f9d7ad946cf050f6a06b75a4a1 Mon Sep 17 00:00:00 2001
From: Joel Rosdahl <joel@rosdahl.net>
Date: Thu, 3 Nov 2022 20:45:21 +0100
Subject: [PATCH] fix: Hash variables that affect Clang version on macOS

Fixes #1205.
---
 src/ccache.cpp | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/ccache.cpp b/src/ccache.cpp
index 392818ff3..9bc5c5f2b 100644
--- a/src/ccache.cpp
+++ b/src/ccache.cpp
@@ -1376,11 +1376,17 @@ hash_common_info(const Context& ctx,
 
   // Hash variables that may affect the compilation.
   const char* always_hash_env_vars[] = {
-    // From <https://gcc.gnu.org/onlinedocs/gcc/Environment-Variables.html>:
+    // From <https://gcc.gnu.org/onlinedocs/gcc/Environment-Variables.html>
+    // (note: SOURCE_DATE_EPOCH is handled in hash_source_code_string()):
     "COMPILER_PATH",
     "GCC_COMPARE_DEBUG",
     "GCC_EXEC_PREFIX",
-    // Note: SOURCE_DATE_EPOCH is handled in hash_source_code_string().
+#ifdef __APPLE__
+    // On macOS, /usr/bin/clang is a compiler wrapper that switches compiler
+    // based on at least these variables:
+    "DEVELOPER_DIR",
+    "MACOSX_DEPLOYMENT_TARGET",
+#endif
   };
   for (const char* name : always_hash_env_vars) {
     const char* value = getenv(name);
-- 
2.47.2