--- dyld/dyld-45.3/src/dyld.cpp
+++ dyld/dyld-46.12/src/dyld.cpp
@@ -1054,6 +1054,13 @@
 						return true;
 					}
 					break;
+				case CPU_TYPE_X86_64:
+					if ( (cpu_subtype_t)OSSwapBigToHostInt32(archs[i].cpusubtype) == CPU_SUBTYPE_X86_64_ALL ) {
+						*offset = OSSwapBigToHostInt32(archs[i].offset);
+						*len = OSSwapBigToHostInt32(archs[i].size);
+						return true;
+					}
+					break;
 			}
 		}
 	}
@@ -1133,6 +1140,10 @@
 					if ( mh->cpusubtype == CPU_SUBTYPE_I386_ALL ) 
 						return true;
 					break;					
+				case CPU_TYPE_X86_64:
+					if ( mh->cpusubtype == CPU_SUBTYPE_X86_64_ALL ) 
+ 						return true;
+					break;		
 			}
 		}
 	}
@@ -1694,7 +1705,7 @@
 	
 #if __ppc__ || __ppc64__
 	__asm__  ("trap");
-#elif __i386__
+#elif __i386__ || __x86_64__
 	__asm__  ("int3");
 #else
 	#error unknown architecture
@@ -1906,21 +1917,16 @@
 	gLinkContext.apple					= apple;
 }
 
-static bool checkEmulation()
-{
-#if __i386__
+static bool isRosetta()
+{
 	int mib[] = { CTL_KERN, KERN_CLASSIC, getpid() };
 	int is_classic = 0;
 	size_t len = sizeof(int);
 	int ret = sysctl(mib, 3, &is_classic, &len, NULL, 0);
 	if ((ret != -1) && is_classic) {
-		// When a 32-bit ppc program is run under emulation on an Intel processor,
-		// we want any i386 dylibs (e.g. the emulator) to not load in the shared region
-		// because the shared region is being used by ppc dylibs
-		gLinkContext.sharedRegionMode = ImageLoader::kDontUseSharedRegion;
+		// we're running under Rosetta 
 		return true;
 	}
-#endif
 	return false;
 }
 
@@ -1982,13 +1988,20 @@
 	// set pthread keys to dyld range
 	__pthread_tsd_first = 1;
 	
-	bool isEmulated = checkEmulation();
 	// Pickup the pointer to the exec path.
 	sExecPath = apple[0];
-	if (isEmulated) {
-		// under Rosetta 
+	bool ignoreEnvironmentVariables = false;
+#if __i386__
+	if ( isRosetta() ) {
+		// under Rosetta (x86 side)
+		// When a 32-bit ppc program is run under emulation on an Intel processor,
+		// we want any i386 dylibs (e.g. any used by Rosetta) to not load in the shared region
+		// because the shared region is being used by ppc dylibs
+		gLinkContext.sharedRegionMode = ImageLoader::kDontUseSharedRegion;
 		sExecPath = strdup(apple[0] + strlen(apple[0]) + 1);
-	}
+		ignoreEnvironmentVariables = true;
+	}
+#endif
 	if ( sExecPath[0] != '/' ) {
 		// have relative path, use cwd to make absolute
 		char cwdbuff[MAXPATHLEN];
@@ -2006,7 +2019,7 @@
 	if ( issetugid() )
 		pruneEnvironmentVariables(envp, &apple);
 	else
-		checkEnvironmentVariables(envp, isEmulated);
+		checkEnvironmentVariables(envp, ignoreEnvironmentVariables);
 	if ( sEnv.DYLD_PRINT_OPTS ) 
 		printOptions(argv);
 	if ( sEnv.DYLD_PRINT_ENV ) 
@@ -2064,8 +2077,9 @@
 		fprintf(stderr, "dyld: launch failed\n");
 	}
 	
+
 	// Link in any inserted libraries.  
-	// Do this after link main executable so any extra libraries pulled in by inserted libraries are at end of flat namespace
+	// Do this after linking main executable so any extra libraries pulled in by inserted libraries are at end of flat namespace
 	if ( insertLibrariesCount > 0 ) {
 		for (int i=0; i < insertLibrariesCount; ++i) {
 			try {