Address case when user has a specific target

Signed-off-by: Santiago Figueroa Manrique <figueroa1395@gmail.com>

Author: figueroa1395

setup.py

@@ -18,7 +18,9 @@
     if_win = True
 elif platform.system() in ["Linux", "Darwin"]:
     if_win = False
-    if platform.system() == "Darwin":
+    if platform.system() == "Darwin" and (
+        "MACOSX_DEPLOYMENT_TARGET" not in os.environ or float(os.environ["MACOSX_DEPLOYMENT_TARGET"]) < 13.3
+    ):
         os.environ["MACOSX_DEPLOYMENT_TARGET"] = "13.3"
 else:
     raise SystemError("Only Windows, Linux, or MacOS is supported!")