Add availability to new CInterop typealiases

Author: jrflat

Sources/System/FileSystem/FileFlags.swift

@@ -39,10 +39,6 @@
 // |------------------|---------------|---------------|---------------|
 
 #if SYSTEM_PACKAGE_DARWIN || os(FreeBSD) || os(OpenBSD)
-@available(System 99, *)
-extension CInterop {
-  public typealias FileFlags = UInt32
-}
 
 /// File-specific flags found in the `st_flags` property of a `stat` struct
 /// or used as input to `chflags()`.

Sources/System/Internals/CInterop.swift

@@ -78,12 +78,18 @@ public enum CInterop {
   /// on API.
   public typealias PlatformUnicodeEncoding = UTF8
   #endif
+}
 
-  #if !os(Windows)
+#if !os(Windows)
+@available(System 99, *)
+extension CInterop {
   public typealias Stat = stat
   public typealias DeviceID = dev_t
   public typealias Inode = ino_t
   public typealias UserID = uid_t
   public typealias GroupID = gid_t
+  #if SYSTEM_PACKAGE_DARWIN || os(FreeBSD) || os(OpenBSD)
+  public typealias FileFlags = UInt32
   #endif
 }
+#endif

Sources/System/Internals/Exports.swift

@@ -91,15 +91,19 @@ internal func system_strlen(_ s: UnsafeMutablePointer<CChar>) -> Int {
 }
 
 #if !os(Windows)
+@available(System 99, *)
 internal func system_stat(_ p: UnsafePointer<CChar>, _ s: inout CInterop.Stat) -> Int32 {
   stat(p, &s)
 }
+@available(System 99, *)
 internal func system_lstat(_ p: UnsafePointer<CChar>, _ s: inout CInterop.Stat) -> Int32 {
   lstat(p, &s)
 }
+@available(System 99, *)
 internal func system_fstat(_ fd: CInt, _ s: inout CInterop.Stat) -> Int32 {
   fstat(fd, &s)
 }
+@available(System 99, *)
 internal func system_fstatat(_ fd: CInt, _ p: UnsafePointer<CChar>, _ s: inout CInterop.Stat, _ flags: CInt) -> Int32 {
   fstatat(fd, p, &s, flags)
 }