Remove _GNU_SOURCE define and AT_EMPTY_PATH for now

Author: jrflat

Package.swift

@@ -87,7 +87,6 @@ let swiftSettings = swiftSettingsAvailability + swiftSettingsCI + [
 
 let cSettings: [CSetting] = [
   .define("_CRT_SECURE_NO_WARNINGS", .when(platforms: [.windows])),
-  .define("_GNU_SOURCE", .when(platforms: [.linux])),
 ]
 
 #if SYSTEM_ABI_STABLE

Sources/System/FileSystem/Stat.swift

@@ -86,15 +86,16 @@ public struct Stat: RawRepresentable, Sendable {
     public static var resolveBeneath: Flags { Flags(rawValue: _AT_RESOLVE_BENEATH) }
     #endif
 
-    #if os(FreeBSD) || os(Linux) || os(Android)
-    /// If the path is an empty string (or `NULL` since Linux 6.11),
-    /// return information about the given file descriptor.
-    ///
-    /// The corresponding C constant is `AT_EMPTY_PATH`.
-    /// - Note: Only available on FreeBSD, Linux, and Android.
-    @_alwaysEmitIntoClient
-    public static var emptyPath: Flags { Flags(rawValue: _AT_EMPTY_PATH) }
-    #endif
+    // TODO: Re-enable when _GNU_SOURCE can be defined.
+//    #if os(FreeBSD) || os(Linux) || os(Android)
+//    /// If the path is an empty string (or `NULL` since Linux 6.11),
+//    /// return information about the given file descriptor.
+//    ///
+//    /// The corresponding C constant is `AT_EMPTY_PATH`.
+//    /// - Note: Only available on FreeBSD, Linux, and Android.
+//    @_alwaysEmitIntoClient
+//    public static var emptyPath: Flags { Flags(rawValue: _AT_EMPTY_PATH) }
+//    #endif
   }
 
   // MARK: Initializers

Sources/System/Internals/Constants.swift

@@ -663,10 +663,11 @@ internal var _AT_SYMLINK_NOFOLLOW_ANY: CInt { AT_SYMLINK_NOFOLLOW_ANY }
 internal var _AT_RESOLVE_BENEATH: CInt { AT_RESOLVE_BENEATH }
 #endif
 
-#if os(FreeBSD) || os(Linux) || os(Android)
-@_alwaysEmitIntoClient
-internal var _AT_EMPTY_PATH: CInt { AT_EMPTY_PATH }
-#endif
+// TODO: Re-enable when _GNU_SOURCE can be defined.
+//#if os(FreeBSD) || os(Linux) || os(Android)
+//@_alwaysEmitIntoClient
+//internal var _AT_EMPTY_PATH: CInt { AT_EMPTY_PATH }
+//#endif
 
 // MARK: - File Mode / File Type
 

Tests/SystemTests/StatTests.swift

@@ -81,7 +81,6 @@ private struct StatTests {
   }
 
   @Test
-  @available(macOS 13.0, iOS 16.0, watchOS 9.0, tvOS 16.0, *)
   func followSymlinkInits() async throws {
     try withTemporaryFilePath(basename: "Stat_followSymlinkInits") { tempDir in
       let targetFilePath = tempDir.appending("target.txt")
@@ -98,17 +97,15 @@ private struct StatTests {
         }
       }
 
-      #if !os(WASI) // Can't open an fd to a symlink on WASI (no O_PATH)
+      // Can't open an fd to a symlink on WASI (no O_PATH)
+      // On non-Darwin, we need O_PATH | O_NOFOLLOW to open the symlink
+      // directly, but O_PATH requires _GNU_SOURCE be defined (TODO).
       #if SYSTEM_PACKAGE_DARWIN
       let symlinkFD = try FileDescriptor.open(symlinkPath, .readOnly, options: .symlink)
-      #else
-      // Need O_PATH | O_NOFOLLOW to open the symlink directly
-      let symlinkFD = try FileDescriptor.open(symlinkPath, .readOnly, options: [.path, .noFollow])
-      #endif
       defer {
         try? symlinkFD.close()
       }
-      #endif // !os(WASI)
+      #endif
 
       let targetStat = try targetFilePath.stat()
       let originalTargetAccessTime = targetStat.st_atim
@@ -130,7 +127,7 @@ private struct StatTests {
       stat.st_atim = originalTargetAccessTime
       #expect(stat == targetStat)
 
-      #if !os(WASI)
+      #if SYSTEM_PACKAGE_DARWIN
       stat = try symlinkFD.stat()
       stat.st_atim = originalSymlinkAccessTime
       #expect(stat == symlinkStat)
@@ -142,7 +139,7 @@ private struct StatTests {
       stat.st_atim = originalTargetAccessTime
       #expect(stat == targetStat)
 
-      #if !os(WASI)
+      #if SYSTEM_PACKAGE_DARWIN
       stat = try Stat(symlinkFD)
       stat.st_atim = originalSymlinkAccessTime
       #expect(stat == symlinkStat)
@@ -400,11 +397,12 @@ private struct StatTests {
 
 }
 
-#if !SYSTEM_PACKAGE_DARWIN && !os(WASI)
-private extension FileDescriptor.OpenOptions {
-  static var path: Self { Self(rawValue: O_PATH) }
-}
-#endif
+// TODO: Re-enable for testing when _GNU_SOURCE can be defined.
+//#if !SYSTEM_PACKAGE_DARWIN && !os(WASI)
+//private extension FileDescriptor.OpenOptions {
+//  static var path: Self { Self(rawValue: O_PATH) }
+//}
+//#endif
 
 // Comparison operators for timespec until UTCClock.Instant properties are available
 private func >= (lhs: timespec, rhs: timespec) -> Bool {