diff --git a/pkgs/development/tools/build-managers/cmake/setup-hook.sh b/pkgs/development/tools/build-managers/cmake/setup-hook.sh
index 5479067d637e..87bbefa6bbfa 100755
--- a/pkgs/development/tools/build-managers/cmake/setup-hook.sh
+++ b/pkgs/development/tools/build-managers/cmake/setup-hook.sh
@@ -50,6 +50,9 @@ cmakeConfigurePhase() {
     # because we usually do not package the framework
     cmakeFlags="-DCMAKE_FIND_FRAMEWORK=last $cmakeFlags"
 
+    # on macOS i686 was only relevant for 10.5 or earlier.
+    cmakeFlags="-DCMAKE_OSX_ARCHITECTURES=x86_64 $cmakeFlags"
+
     # we never want to use the global macOS SDK
     cmakeFlags="-DCMAKE_OSX_SYSROOT= $cmakeFlags"
 
diff --git a/pkgs/stdenv/darwin/default.nix b/pkgs/stdenv/darwin/default.nix
index 7a9c20fd6a7b..4f91d18a3764 100644
--- a/pkgs/stdenv/darwin/default.nix
+++ b/pkgs/stdenv/darwin/default.nix
@@ -34,7 +34,6 @@ in rec {
     export NIX_ENFORCE_NO_NATIVE=''${NIX_ENFORCE_NO_NATIVE-1}
     export NIX_ENFORCE_PURITY=''${NIX_ENFORCE_PURITY-1}
     export NIX_IGNORE_LD_THROUGH_GCC=1
-    export CMAKE_OSX_ARCHITECTURES=x86_64
     export SDKROOT=
 
     # Ensure consistent LC_VERSION_MIN_MACOSX and remove LC_UUID.