diff --git a/Sources/Foundation/Data.swift b/Sources/Foundation/Data.swift
index a808240b33..706b857bf2 100644
--- a/Sources/Foundation/Data.swift
+++ b/Sources/Foundation/Data.swift
@@ -26,6 +26,13 @@
 @usableFromInline let memset = WASILibc.memset
 @usableFromInline let memcpy = WASILibc.memcpy
 @usableFromInline let memcmp = WASILibc.memcmp
+#elseif canImport(CRT)
+@usableFromInline let calloc = ucrt.calloc
+@usableFromInline let malloc = ucrt.malloc
+@usableFromInline let free = ucrt.free
+@usableFromInline let memset = ucrt.memset
+@usableFromInline let memcpy = ucrt.memcpy
+@usableFromInline let memcmp = ucrt.memcmp
 #endif
 
 #if !canImport(Darwin)
diff --git a/Sources/Foundation/FileHandle.swift b/Sources/Foundation/FileHandle.swift
index e282628602..097b18ca1b 100644
--- a/Sources/Foundation/FileHandle.swift
+++ b/Sources/Foundation/FileHandle.swift
@@ -25,10 +25,11 @@ fileprivate let _close = Glibc.close(_:)
 #endif
 
 #if canImport(WinSDK)
-// We used to get the copy that was re-exported by CoreFoundation
+import WinSDK.core
+// We used to get the alias that was re-exported by CoreFoundation
 // but we want to explicitly depend on its types in this file,
 // so we need to make sure Swift doesn't think it's @_implementationOnly.
-import WinSDK
+import struct WinSDK.HANDLE
 #endif
 
 extension NSError {
diff --git a/Sources/Foundation/FileManager+Win32.swift b/Sources/Foundation/FileManager+Win32.swift
index a3a75f6ae4..0629ab7029 100644
--- a/Sources/Foundation/FileManager+Win32.swift
+++ b/Sources/Foundation/FileManager+Win32.swift
@@ -10,6 +10,9 @@
 @_implementationOnly import CoreFoundation
 
 #if os(Windows)
+import WinSDK.core
+import struct WinSDK.FILETIME
+
 internal func joinPath(prefix: String, suffix: String) -> String {
     var pszPath: PWSTR?
 
@@ -1035,4 +1038,8 @@ extension FileManager.NSPathDirectoryEnumerator {
 
 }
 
+// FIXME: This is a workaround for CoreFoundation/WinSDK overload
+// of the same constants with different types.  We should prevent
+// CoreFoundation from re-exporting them.
+fileprivate let INVALID_FILE_ATTRIBUTES = DWORD(bitPattern: -1)
 #endif
diff --git a/Sources/Foundation/FileManager.swift b/Sources/Foundation/FileManager.swift
index ec0f255817..be3549265d 100644
--- a/Sources/Foundation/FileManager.swift
+++ b/Sources/Foundation/FileManager.swift
@@ -18,6 +18,7 @@ fileprivate let UF_HIDDEN: Int32 = 1
 @_implementationOnly import CoreFoundation
 #if os(Windows)
 import CRT
+import WinSDK.core
 #endif
 
 #if os(Windows)
diff --git a/Sources/Foundation/Host.swift b/Sources/Foundation/Host.swift
index d21f9b702a..da2e57afb6 100644
--- a/Sources/Foundation/Host.swift
+++ b/Sources/Foundation/Host.swift
@@ -9,6 +9,10 @@
 
 @_implementationOnly import CoreFoundation
 
+#if os(Windows)
+import WinSDK.core
+#endif
+
 #if os(Android)
     // Android Glibc differs a little with respect to the Linux Glibc.
 
diff --git a/Sources/Foundation/NSError.swift b/Sources/Foundation/NSError.swift
index d5a8f67a07..73a4761d76 100644
--- a/Sources/Foundation/NSError.swift
+++ b/Sources/Foundation/NSError.swift
@@ -16,6 +16,7 @@ import Darwin
 import Glibc
 #elseif canImport(CRT)
 import CRT
+import WinSDK
 #endif
 
 @_implementationOnly import CoreFoundation
diff --git a/Sources/Foundation/NSPathUtilities.swift b/Sources/Foundation/NSPathUtilities.swift
index b4c6a2889e..eb7b112415 100644
--- a/Sources/Foundation/NSPathUtilities.swift
+++ b/Sources/Foundation/NSPathUtilities.swift
@@ -9,6 +9,11 @@
 
 @_implementationOnly import CoreFoundation
 
+#if os(Windows)
+import WinSDK.core
+#endif
+
+
 #if os(Windows)
 let validPathSeps: [Character] = ["\\", "/"]
 #else
diff --git a/Sources/Foundation/NSSwiftRuntime.swift b/Sources/Foundation/NSSwiftRuntime.swift
index 04958446d7..4879ae62bc 100644
--- a/Sources/Foundation/NSSwiftRuntime.swift
+++ b/Sources/Foundation/NSSwiftRuntime.swift
@@ -14,7 +14,7 @@
 // This mimics the behavior of the swift sdk overlay on Darwin
 #if os(macOS) || os(iOS) || os(tvOS) || os(watchOS)
 @_exported import Darwin
-#elseif os(Linux) || os(Android) || CYGWIN || os(OpenBSD)
+#elseif os(Linux) || os(Android) || os(Cygwin) || os(OpenBSD)
 @_exported import Glibc
 #elseif os(WASI)
 @_exported import WASILibc
diff --git a/Sources/Foundation/NSURL.swift b/Sources/Foundation/NSURL.swift
index 38c260d17d..c73864dfc9 100644
--- a/Sources/Foundation/NSURL.swift
+++ b/Sources/Foundation/NSURL.swift
@@ -17,6 +17,8 @@ internal let kCFURLWindowsPathStyle = CFURLPathStyle.cfurlWindowsPathStyle
 import Darwin
 #elseif canImport(Glibc)
 import Glibc
+#elseif canImport(CRT)
+import CRT
 #endif
 
 // NOTE: this represents PLATFORM_PATH_STYLE
diff --git a/Sources/Foundation/Process.swift b/Sources/Foundation/Process.swift
index 8d4834320e..7ad81ce3fb 100644
--- a/Sources/Foundation/Process.swift
+++ b/Sources/Foundation/Process.swift
@@ -11,13 +11,15 @@
 
 #if canImport(Darwin)
 import Darwin
+#elseif canImport(WinSDK)
+import WinSDK
 #endif
 
 #if canImport(WinSDK)
-// We used to get the copy that was re-exported by CoreFoundation
+// We used to get the alias that was re-exported by CoreFoundation
 // but we want to explicitly depend on its types in this file,
 // so we need to make sure Swift doesn't think it's @_implementationOnly.
-import WinSDK
+import struct WinSDK.HANDLE
 #endif
 
 extension Process {
@@ -1162,6 +1164,13 @@ open class Process: NSObject {
 }
 
 extension Process {
-    
     public static let didTerminateNotification = NSNotification.Name(rawValue: "NSTaskDidTerminateNotification")
 }
+
+#if os(Windows)
+// FIXME: This is a workaround for CoreFoundation/WinSDK overload
+// of the same constants with different types.  We should prevent
+// CoreFoundation from re-exporting them.
+fileprivate let HANDLE_FLAG_INHERIT = DWORD(0x00000001)
+fileprivate let STARTF_USESTDHANDLES = DWORD(0x00000100)
+#endif
diff --git a/Sources/Foundation/ProcessInfo.swift b/Sources/Foundation/ProcessInfo.swift
index 92ad64ef19..d34dfbd244 100644
--- a/Sources/Foundation/ProcessInfo.swift
+++ b/Sources/Foundation/ProcessInfo.swift
@@ -9,6 +9,10 @@
 
 @_implementationOnly import CoreFoundation
 
+#if os(Windows)
+import WinSDK
+#endif
+
 public struct OperatingSystemVersion {
     public var majorVersion: Int
     public var minorVersion: Int
diff --git a/Sources/Foundation/Thread.swift b/Sources/Foundation/Thread.swift
index 7fc74fb160..8ad287cfd7 100644
--- a/Sources/Foundation/Thread.swift
+++ b/Sources/Foundation/Thread.swift
@@ -11,6 +11,8 @@
 
 #if canImport(Glibc)
 import Glibc
+#elseif canImport(WinSDK)
+import WinSDK.core
 #endif
 
 // WORKAROUND_SR9811