Fix 64-bit Mac compilation errors in src/crypto.

third_party/mach_override/mach_override.c

Index: third_party/mach_override/mach_override.c
===================================================================
--- third_party/mach_override/mach_override.c	(revision 147091)
+++ third_party/mach_override/mach_override.c	(working copy)
@@ -371,7 +371,7 @@
 		if( !err ) {
 			assert( sizeof( BranchIsland ) <= pageSize );
 #if defined(__x86_64__)
-			vm_address_t first = (uint64_t)originalFunctionAddress & ~(uint64_t)(((uint64_t)1 << 31) - 1) | ((uint64_t)1 << 31); // start in the middle of the page?
+			vm_address_t first = ((uint64_t)originalFunctionAddress & ~(uint64_t)(((uint64_t)1 << 31) - 1)) | ((uint64_t)1 << 31); // start in the middle of the page?
 			vm_address_t last = 0x0;
 #else
 			vm_address_t first = 0xffc00000;