diff --git a/pkgs/build-support/wrapper-common/darwin-sdk-setup.bash b/pkgs/build-support/wrapper-common/darwin-sdk-setup.bash
index 8c6a337a8fca..3b31a4aa6981 100644
--- a/pkgs/build-support/wrapper-common/darwin-sdk-setup.bash
+++ b/pkgs/build-support/wrapper-common/darwin-sdk-setup.bash
@@ -8,9 +8,9 @@ if [[ "@darwinMinVersion@" ]]; then
 
     # Allow wrapped compilers to do something useful when no `DEVELOPER_DIR` is set, which can happen when
     # the compiler is run outside of a stdenv or intentionally in an environment with no environment variables set.
-    DEVELOPER_DIR=${DEVELOPER_DIR_@suffixSalt@:-@fallback_sdk@}
+    export DEVELOPER_DIR=${DEVELOPER_DIR_@suffixSalt@:-@fallback_sdk@}
 
     # xcbuild needs `SDKROOT` to be the name of the SDK, which it sets in its own wrapper,
     # but compilers expect it to point to the absolute path.
-    SDKROOT="$DEVELOPER_DIR/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk"
+    export SDKROOT="$DEVELOPER_DIR/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk"
 fi