[cli] Update lib linking for darwin only case

pyhmy/cli.py

@@ -368,15 +368,16 @@ def download(path="./bin/hmy", replace=True, verbose=True):
         os.chdir(old_cwd)
 
     env = os.environ.copy()
+    if sys.platform.startswith("darwin"):  # Dynamic linking for darwin
+        try:
             files_in_parent_dir = set(os.listdir(parent_dir))
             if files_in_parent_dir.intersection(_libs) == _libs:
-        if sys.platform.startswith("linux"):
-            env["LD_LIBRARY_PATH"] = parent_dir
-        else:
                 env["DYLD_FALLBACK_LIBRARY_PATH"] = parent_dir
             elif os.path.exists(f"{get_gopath()}/src/github.com/harmony-one/bls") \
                     and os.path.exists(f"{get_gopath()}/src/github.com/harmony-one/mcl"):
                 env.update(get_bls_build_variables())
             else:
                 raise RuntimeWarning(f"Could not get environment for downloaded hmy CLI at `{path}`")
+        except Exception as e:
+            raise RuntimeWarning(f"Could not get environment for downloaded hmy CLI at `{path}`") from e
     return env