mesa: Limit the devDoesNotDependOnLLVM test to Linux

The required modifications in the postInstall phase are only applied on
Linux and the test currently fails on Darwin:
https://github.com/NixOS/nixpkgs/runs/5344236204
> building '/nix/store/45s58pv9j6a19wr9izx49s6i0i4qshxs-mesa-dev-does-not-depend-on-llvm.drv'...
> error: output '/nix/store/czmszfcwdx87vx2wf80lhp3h9skqqcfs-mesa-dev-does-not-depend-on-llvm' is not allowed to refer to the following paths:
>          /nix/store/cwb5g57al7iizw456ah9rk49cxb47wi3-mesa-21.3.7-drivers

1 files changed, 8 insertions, 6 deletions

diff --git a/pkgs/development/libraries/mesa/default.nix b/pkgs/development/libraries/mesa/default.nix
index b91e140345de8..1fb573931b6d0 100644
--- a/pkgs/development/libraries/mesa/default.nix
+++ b/pkgs/development/libraries/mesa/default.nix
@@ -252,12 +252,14 @@ self = stdenv.mkDerivation {
     inherit (libglvnd) driverLink;
     inherit llvmPackages;
 
-    tests.devDoesNotDependOnLLVM = stdenv.mkDerivation {
-      name = "mesa-dev-does-not-depend-on-llvm";
-      buildCommand = ''
-        echo ${self.dev} >>$out
-      '';
-      disallowedRequisites = [ llvmPackages.llvm self.drivers ];
+    tests = lib.optionalAttrs stdenv.isLinux {
+      devDoesNotDependOnLLVM = stdenv.mkDerivation {
+        name = "mesa-dev-does-not-depend-on-llvm";
+        buildCommand = ''
+          echo ${self.dev} >>$out
+        '';
+        disallowedRequisites = [ llvmPackages.llvm self.drivers ];
+      };
     };
   };