mim-solvers: enable multithread

pkgs/by-name/mi/mim-solvers/package.nix

@@ -28,7 +28,9 @@ stdenv.mkDerivation (finalAttrs: {
     pkg-config
   ];
 
-  buildInputs = lib.optional stdenv.hostPlatform.isDarwin llvmPackages.openmp;
+  buildInputs = lib.optional (
+    stdenv.hostPlatform.isDarwin && crocoddyl.withMultithread
+  ) llvmPackages.openmp;
 
   propagatedBuildInputs = [
     crocoddyl
@@ -38,6 +40,7 @@ stdenv.mkDerivation (finalAttrs: {
   cmakeFlags = [
     (lib.cmakeBool "BUILD_PYTHON_INTERFACE" false)
     (lib.cmakeBool "BUILD_WITH_PROXSUITE" true)
+    (lib.cmakeBool "BUILD_WITH_MULTITHREADS" crocoddyl.withMultithread)
   ];
 
   nativeCheckInputs = [