Fixed getting windows version. The former function is no longer working on Windows 10. Also fixed the struct to use correct win32 names

core/sys/windows/ntdll.odin

@@ -0,0 +1,8 @@
+package version
+
+foreign import ntdll_lib "system:ntdll.lib"
+
+@(default_calling_convention="std")
+foreign ntdll_lib {
+    RtlGetVersion :: proc(lpVersionInformation: ^OSVERSIONINFOEXW) -> NTSTATUS ---;
+}