Add fallback impls for sleep and time functions

- `GetSystemTimePreciseAsFileTime`: fall back to `GetSystemTimeAsFileTime`
- `GetSystemTimeAsFileTime`: fall back to `GetSystemTime` and `SystemTimeToFileTime`
  - (only necessary for NT 3.1)
- `SwitchToThread`: fall back to `Sleep(0)`
- `CreateWaitableTimerExW`: optional import, fallback already in place

Author: seritools

library/std/src/sys/pal/windows/c.rs

@@ -140,7 +140,7 @@ compat_fn_with_fallback! {
 
     // >= Win8 / Server 2012
     // https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimepreciseasfiletime
-    #[cfg(target_vendor = "win7")]
+    #[cfg(any(target_vendor = "win7", target_vendor = "rust9x"))]
     pub fn GetSystemTimePreciseAsFileTime(lpsystemtimeasfiletime: *mut FILETIME) -> () {
         unsafe { GetSystemTimeAsFileTime(lpsystemtimeasfiletime) }
     }
@@ -346,3 +346,35 @@ compat_fn_with_fallback! {
     // https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-setthreadstackguarantee
     pub fn SetThreadStackGuarantee(stacksizeinbytes: *mut u32) -> BOOL { TRUE }
 }
+
+#[cfg(target_vendor = "rust9x")]
+compat_fn_with_fallback! {
+    pub static KERNEL32: &CStr = c"kernel32" => { load: false, unicows: false };
+    // >= 95 / NT 3.5
+    // https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimeasfiletime
+    pub fn GetSystemTimeAsFileTime(lpSystemTimeAsFileTime: *mut FILETIME) {
+        unsafe {
+            // implementation based on old MSDN docs
+            let mut st: SYSTEMTIME = crate::mem::zeroed();
+            GetSystemTime(&mut st);
+            crate::sys::cvt(SystemTimeToFileTime(&st, lpSystemTimeAsFileTime)).unwrap();
+        }
+    }
+    // >= NT 4
+    // https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-switchtothread
+    pub fn SwitchToThread() -> BOOL {
+        unsafe { Sleep(0); }
+        TRUE
+    }
+
+    // >= Vista / Server 2008
+    // https://learn.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-createwaitabletimerexw
+    pub fn CreateWaitableTimerExW(
+        lptimerattributes: *const SECURITY_ATTRIBUTES,
+        lptimername: PCWSTR,
+        dwflags: u32,
+        dwdesiredaccess: u32
+    ) -> HANDLE {
+        ptr::null_mut()
+    }
+}

library/std/src/sys/pal/windows/c/bindings.txt

@@ -2491,6 +2491,7 @@ Windows.Win32.System.Pipes.PIPE_TYPE_MESSAGE
 Windows.Win32.System.Pipes.PIPE_WAIT
 Windows.Win32.System.SystemInformation.GetSystemDirectoryW
 Windows.Win32.System.SystemInformation.GetSystemInfo
+Windows.Win32.System.SystemInformation.GetSystemTime
 Windows.Win32.System.SystemInformation.GetSystemTimeAsFileTime
 Windows.Win32.System.SystemInformation.GetSystemTimePreciseAsFileTime
 Windows.Win32.System.SystemInformation.GetVersion
@@ -2616,5 +2617,6 @@ Windows.Win32.System.Threading.WaitForMultipleObjects
 Windows.Win32.System.Threading.WaitForSingleObject
 Windows.Win32.System.Threading.WakeAllConditionVariable
 Windows.Win32.System.Threading.WakeConditionVariable
+Windows.Win32.System.Time.SystemTimeToFileTime
 Windows.Win32.System.WindowsProgramming.PROGRESS_CONTINUE
 Windows.Win32.UI.Shell.GetUserProfileDirectoryW

library/std/src/sys/pal/windows/c/windows_sys.rs

@@ -61,6 +61,7 @@ windows_targets::link!("kernel32.dll" "system" fn GetProcessId(process : HANDLE)
 windows_targets::link!("kernel32.dll" "system" fn GetStdHandle(nstdhandle : STD_HANDLE) -> HANDLE);
 windows_targets::link!("kernel32.dll" "system" fn GetSystemDirectoryW(lpbuffer : PWSTR, usize : u32) -> u32);
 windows_targets::link!("kernel32.dll" "system" fn GetSystemInfo(lpsysteminfo : *mut SYSTEM_INFO));
+windows_targets::link!("kernel32.dll" "system" fn GetSystemTime(lpsystemtime : *mut SYSTEMTIME));
 windows_targets::link!("kernel32.dll" "system" fn GetSystemTimeAsFileTime(lpsystemtimeasfiletime : *mut FILETIME));
 windows_targets::link!("kernel32.dll" "system" fn GetSystemTimePreciseAsFileTime(lpsystemtimeasfiletime : *mut FILETIME));
 windows_targets::link!("kernel32.dll" "system" fn GetTempPathW(nbufferlength : u32, lpbuffer : PWSTR) -> u32);
@@ -102,6 +103,7 @@ windows_targets::link!("kernel32.dll" "system" fn Sleep(dwmilliseconds : u32));
 windows_targets::link!("kernel32.dll" "system" fn SleepConditionVariableSRW(conditionvariable : *mut CONDITION_VARIABLE, srwlock : *mut SRWLOCK, dwmilliseconds : u32, flags : u32) -> BOOL);
 windows_targets::link!("kernel32.dll" "system" fn SleepEx(dwmilliseconds : u32, balertable : BOOL) -> u32);
 windows_targets::link!("kernel32.dll" "system" fn SwitchToThread() -> BOOL);
+windows_targets::link!("kernel32.dll" "system" fn SystemTimeToFileTime(lpsystemtime : *const SYSTEMTIME, lpfiletime : *mut FILETIME) -> BOOL);
 windows_targets::link!("kernel32.dll" "system" fn TerminateProcess(hprocess : HANDLE, uexitcode : u32) -> BOOL);
 windows_targets::link!("kernel32.dll" "system" fn TlsAlloc() -> u32);
 windows_targets::link!("kernel32.dll" "system" fn TlsFree(dwtlsindex : u32) -> BOOL);
@@ -3056,6 +3058,18 @@ pub type SYNCHRONIZATION_ACCESS_RIGHTS = u32;
 pub const SYNCHRONIZE: FILE_ACCESS_RIGHTS = 1048576u32;
 #[repr(C)]
 #[derive(Clone, Copy)]
+pub struct SYSTEMTIME {
+    pub wYear: u16,
+    pub wMonth: u16,
+    pub wDayOfWeek: u16,
+    pub wDay: u16,
+    pub wHour: u16,
+    pub wMinute: u16,
+    pub wSecond: u16,
+    pub wMilliseconds: u16,
+}
+#[repr(C)]
+#[derive(Clone, Copy)]
 pub struct SYSTEM_INFO {
     pub Anonymous: SYSTEM_INFO_0,
     pub dwPageSize: u32,