Stubtest fixes (#5391)

stdlib/grp.pyi

@@ -7,5 +7,5 @@ class struct_group(NamedTuple):
     gr_mem: List[str]
 
 def getgrall() -> List[struct_group]: ...
-def getgrgid(gid: int) -> struct_group: ...
+def getgrgid(id: int) -> struct_group: ...
 def getgrnam(name: str) -> struct_group: ...

stdlib/socket.pyi

@@ -768,7 +768,13 @@ def getnameinfo(sockaddr: Union[Tuple[str, int], Tuple[str, int, int, int]], fla
 def getprotobyname(protocolname: str) -> int: ...
 def getservbyname(servicename: str, protocolname: str = ...) -> int: ...
 def getservbyport(port: int, protocolname: str = ...) -> str: ...
-def socketpair(family: int = ..., type: int = ..., proto: int = ...) -> Tuple[socket, socket]: ...
+
+if sys.platform == "win32":
+    def socketpair(family: int = ..., type: int = ..., proto: int = ...) -> Tuple[socket, socket]: ...
+
+else:
+    def socketpair(family: Optional[int] = ..., type: int = ..., proto: int = ...) -> Tuple[socket, socket]: ...
+
 def ntohl(x: int) -> int: ...  # param & ret val are 32-bit ints
 def ntohs(x: int) -> int: ...  # param & ret val are 16-bit ints
 def htonl(x: int) -> int: ...  # param & ret val are 32-bit ints

stdlib/spwd.pyi

@@ -12,4 +12,4 @@ class struct_spwd(NamedTuple):
     sp_flag: int
 
 def getspall() -> List[struct_spwd]: ...
-def getspnam(name: str) -> struct_spwd: ...
+def getspnam(__arg: str) -> struct_spwd: ...

stdlib/urllib/request.pyi

@@ -1,5 +1,6 @@
 import os
 import ssl
+import sys
 from email.message import Message
 from http.client import HTTPMessage, HTTPResponse, _HTTPConnectionProtocol
 from http.cookiejar import CookieJar
@@ -38,12 +39,22 @@ def urlopen(
 ) -> _UrlopenRet: ...
 def install_opener(opener: OpenerDirector) -> None: ...
 def build_opener(*handlers: Union[BaseHandler, Callable[[], BaseHandler]]) -> OpenerDirector: ...
-def url2pathname(pathname: str) -> str: ...
-def pathname2url(pathname: str) -> str: ...
+
+if sys.platform == "win32":
+    from nturl2path import pathname2url as pathname2url, url2pathname as url2pathname
+else:
+    def url2pathname(pathname: str) -> str: ...
+    def pathname2url(pathname: str) -> str: ...
+
 def getproxies() -> Dict[str, str]: ...
 def parse_http_list(s: str) -> List[str]: ...
 def parse_keqv_list(l: List[str]) -> Dict[str, str]: ...
-def proxy_bypass(host: str) -> Any: ...  # Undocumented
+
+if sys.platform == "win32" or sys.platform == "darwin":
+    def proxy_bypass(host: str) -> Any: ...  # Undocumented
+
+else:
+    def proxy_bypass(host: str, proxies: Optional[Mapping[str, str]] = ...) -> Any: ...  # Undocumented
 
 class Request:
     @property