Improve errno stubs on Windows and MacOS (#8142)

tests/stubtest_allowlists/linux.txt

@@ -12,6 +12,7 @@ selectors.KqueueSelector
 signal.SIGEMT
 signal.SIGINFO
 socket.[A-Z0-9_]+
+errno.[A-Z0-9]+
 
 # Exists at runtime, but missing from stubs
 distutils.msvccompiler.MSVCCompiler.get_msvc_paths

tests/stubtest_allowlists/py3_common.txt

@@ -519,7 +519,6 @@ xml.etree
 xml.sax
 
 # Platform differences that cannot be captured by the type system
-errno.[A-Z0-9]+
 os.O_[A-Z_]+
 (posix.O_[A-Z_]+)?
 (posix.ST_[A-Z]+)?