Add platform checks for various sys values (#4137)

* Add platform checks for various sys values

* Add windows-only constants

stdlib/3/sys.pyi

@@ -19,14 +19,16 @@ _ExcInfo = Tuple[Type[BaseException], BaseException, TracebackType]
 _OptExcInfo = Union[_ExcInfo, Tuple[None, None, None]]
 
 # ----- sys variables -----
-abiflags: str
+if sys.platform != "win32":
+    abiflags: str
 argv: List[str]
 base_exec_prefix: str
 base_prefix: str
 byteorder: str
 builtin_module_names: Sequence[str]  # actually a tuple of strings
 copyright: str
-# dllhandle = 0  # Windows only
+if sys.platform == "win32":
+    dllhandle: int
 dont_write_bytecode: bool
 displayhook: Callable[[object], Any]
 excepthook: Callable[[Type[BaseException], BaseException, TracebackType], Any]
@@ -64,7 +66,8 @@ api_version: int
 warnoptions: Any
 #  Each entry is a tuple of the form (action, message, category, module,
 #    lineno)
-# winver = ''  # Windows only
+if sys.platform == "win32":
+    winver: str
 _xoptions: Dict[Any, Any]
 
 
@@ -141,7 +144,6 @@ def exc_info() -> _OptExcInfo: ...
 def exit(__status: object = ...) -> NoReturn: ...
 def getdefaultencoding() -> str: ...
 if sys.platform != 'win32':
-    # Unix only
     def getdlopenflags() -> int: ...
 def getfilesystemencoding() -> str: ...
 def getrefcount(__object: Any) -> int: ...
@@ -179,8 +181,8 @@ class _WinVersion(Tuple[int, int, int, int,
     product_type: int
     platform_version: Tuple[int, int, int]
 
-
-def getwindowsversion() -> _WinVersion: ...  # Windows only
+if sys.platform == "win32":
+    def getwindowsversion() -> _WinVersion: ...
 
 def intern(__string: str) -> str: ...
 
@@ -190,7 +192,8 @@ if sys.version_info >= (3, 7):
     __breakpointhook__: Any  # contains the original value of breakpointhook
     def breakpointhook(*args: Any, **kwargs: Any) -> Any: ...
 
-def setdlopenflags(__flags: int) -> None: ...  # Linux only
+if sys.platform != "win32":
+    def setdlopenflags(__flags: int) -> None: ...
 def setrecursionlimit(__limit: int) -> None: ...
 def setswitchinterval(__interval: float) -> None: ...
 

tests/stubtest_whitelists/linux.txt

@@ -27,7 +27,6 @@ spwd.getspnam
 spwd.struct_spwd._asdict
 spwd.struct_spwd._make
 spwd.struct_spwd._replace
-sys.getwindowsversion
 time.CLOCK_HIGHRES
 urllib.request.proxy_bypass
 

tests/stubtest_whitelists/win32.txt

@@ -4,8 +4,6 @@ locale.nl_langinfo  # Function that should be moved to _locale and re-exported c
 os.path.join  # Parameter name mismatch
 posixpath.altsep  # Type mismatch
 posixpath.realpath  # Parameter name mismatch
-sys.abiflags  # Not present
-sys.setdlopenflags  # Not present
 urllib.request.pathname2url  # Parameter name mismatch
 urllib.request.url2pathname  # Same