fix typo

setup.py

@@ -503,7 +503,7 @@ class PyBuildExt(build_ext):
             if sys.platform == 'darwin':
                 # In every directory on the search path search for a dynamic
                 # library and then a static library, instead of first looking
-                # for dynamic libraries on the entiry path.
+                # for dynamic libraries on the entire path.
                 # This way a staticly linked custom readline gets picked up
                 # before the (broken) dynamic library in /usr/lib.
                 readline_extra_link_args = ('-Wl,-search_paths_first',)