--- dyld/dyld-733.8/dyld3/APIs_macOS.cpp
+++ dyld/dyld-832.7.3/dyld3/APIs_macOS.cpp
@@ -55,7 +55,7 @@
 
 
 // only in macOS and deprecated 
-#if __MAC_OS_X_VERSION_MIN_REQUIRED
+#if TARGET_OS_OSX
 
 // macOS needs to support an old API that only works with fileype==MH_BUNDLE.
 // In this deprecated API (unlike dlopen), loading and linking are separate steps.
@@ -70,7 +70,7 @@
 
     // verify path exists
      struct stat statbuf;
-    if ( ::stat(path, &statbuf) == -1 )
+    if ( dyld3::stat(path, &statbuf) == -1 )
         return NSObjectFileImageFailure;
 
     // create ofi that just contains path. NSLinkModule does all the work
@@ -98,13 +98,13 @@
     bool usable = false;
     const MachOFile* mf = (MachOFile*)memImage;
     if ( mf->hasMachOMagic() && mf->isMachO(diag, memImageSize) ) {
-        usable = (gAllImages.archs().grade(mf->cputype, mf->cpusubtype) != 0);
+        usable = (gAllImages.archs().grade(mf->cputype, mf->cpusubtype, false) != 0);
     }
     else if ( const FatFile* ff = FatFile::isFatFile(memImage) ) {
         uint64_t sliceOffset;
         uint64_t sliceLen;
         bool     missingSlice;
-        if ( ff->isFatFileWithSlice(diag, memImageSize, gAllImages.archs(), sliceOffset, sliceLen, missingSlice) ) {
+        if ( ff->isFatFileWithSlice(diag, memImageSize, gAllImages.archs(), false, sliceOffset, sliceLen, missingSlice) ) {
             mf = (MachOFile*)((long)memImage+sliceOffset);
             if ( mf->isMachO(diag, sliceLen) ) {
                 usable = true;
@@ -112,7 +112,7 @@
         }
     }
     if ( usable ) {
-        if ( !mf->supportsPlatform(Platform::macOS) )
+        if ( !mf->builtForPlatform(Platform::macOS) )
             usable = false;
     }
     if ( !usable ) {
@@ -343,10 +343,15 @@
 
 static bool flatFindSymbol(const char* symbolName, void** symbolAddress, const mach_header** foundInImageAtLoadAddress)
 {
+    // <rdar://problem/59265987> allow flat lookup to find "_memcpy" even though it is not implemented as that name in any dylib
+    MachOLoaded::DependentToMachOLoaded finder = ^(const MachOLoaded* mh, uint32_t depIndex) {
+        return gAllImages.findDependent(mh, depIndex);
+    };
+
     __block bool result = false;
     gAllImages.forEachImage(^(const LoadedImage& loadedImage, bool& stop) {
         bool resultPointsToInstructions = false;
-        if ( loadedImage.loadedAddress()->hasExportedSymbol(symbolName, nullptr, symbolAddress, &resultPointsToInstructions) ) {
+        if ( loadedImage.loadedAddress()->hasExportedSymbol(symbolName, finder, symbolAddress, &resultPointsToInstructions) ) {
             *foundInImageAtLoadAddress = loadedImage.loadedAddress();
             stop = true;
             result = true;