[SDK] Remove Foundation's last use of _silgen_name (#14484)

No intended functionality change.
diff --git a/stdlib/public/SDK/Foundation/Data.swift b/stdlib/public/SDK/Foundation/Data.swift
index 0de3ecf..9a6b160 100644
--- a/stdlib/public/SDK/Foundation/Data.swift
+++ b/stdlib/public/SDK/Foundation/Data.swift
@@ -38,9 +38,6 @@
 import _SwiftFoundationOverlayShims
 import _SwiftCoreFoundationOverlayShims
     
-@_silgen_name("__NSDataWriteToURL")
-internal func __NSDataWriteToURL(_ data: NSData, _ url: NSURL, _ options: UInt, _ error: NSErrorPointer) -> Bool
-    
 #endif
 
 public final class _DataStorage {
@@ -1407,9 +1404,9 @@
 #else
             if _shouldUseNonAtomicWriteReimplementation(options: options) {
                 var error: NSError? = nil
-                guard __NSDataWriteToURL($0, url as NSURL, options.rawValue, &error) else { throw error! }
+                guard __NSDataWriteToURL($0, url, options, &error) else { throw error! }
             } else {
-                try $0.write(to: url, options: WritingOptions(rawValue: options.rawValue))
+                try $0.write(to: url, options: options)
             }
 #endif
         }
diff --git a/stdlib/public/SDK/Foundation/DataThunks.m b/stdlib/public/SDK/Foundation/DataThunks.m
index c014651..19e21c0 100644
--- a/stdlib/public/SDK/Foundation/DataThunks.m
+++ b/stdlib/public/SDK/Foundation/DataThunks.m
@@ -111,8 +111,8 @@
     return error;
 }
 
-SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
-BOOL __NSDataWriteToURL(NSData *SWIFT_NS_RELEASES_ARGUMENT data, NSURL *SWIFT_NS_RELEASES_ARGUMENT url, NSDataWritingOptions writingOptions, NSError **_Nullable errorPtr) {
+SWIFT_RUNTIME_STDLIB_INTERNAL
+BOOL __NSDataWriteToURL(NSData * _Nonnull data NS_RELEASES_ARGUMENT, NSURL * _Nonnull url NS_RELEASES_ARGUMENT, NSDataWritingOptions writingOptions, NSError **errorPtr) {
     assert((writingOptions & NSDataWritingAtomic) == 0);
 
     NSString *path = url.path;
diff --git a/stdlib/public/SwiftShims/NSDataShims.h b/stdlib/public/SwiftShims/NSDataShims.h
index a4baabd..ce5038d 100644
--- a/stdlib/public/SwiftShims/NSDataShims.h
+++ b/stdlib/public/SwiftShims/NSDataShims.h
@@ -14,7 +14,7 @@
 
 NS_BEGIN_DECLS
 
-typedef void (^NSDataDeallocator)(void *, NSUInteger);
+typedef void (^NSDataDeallocator)(void * _Null_unspecified, NSUInteger);
 FOUNDATION_EXPORT const NSDataDeallocator NSDataDeallocatorVM;
 FOUNDATION_EXPORT const NSDataDeallocator NSDataDeallocatorUnmap;
 FOUNDATION_EXPORT const NSDataDeallocator NSDataDeallocatorFree;
@@ -24,4 +24,6 @@
 - (BOOL)_isCompact;
 @end
 
+BOOL __NSDataWriteToURL(NS_NON_BRIDGED(NSData *) _Nonnull data NS_RELEASES_ARGUMENT, NSURL * _Nonnull url NS_RELEASES_ARGUMENT, NSDataWritingOptions writingOptions, NSError **errorPtr);
+
 NS_END_DECLS