[sanitizer] OFF_T on Mac is u64.

llvm-svn: 174600
diff --git a/compiler-rt/lib/interception/interception.h b/compiler-rt/lib/interception/interception.h
index c8a0543..0067534 100644
--- a/compiler-rt/lib/interception/interception.h
+++ b/compiler-rt/lib/interception/interception.h
@@ -30,7 +30,12 @@
 // WARNING: OFF_T may be different from OS type off_t, depending on the value of
 // _FILE_OFFSET_BITS. This definition of OFF_T matches the ABI of system calls
 // like pread and mmap, as opposed to pread64 and mmap64.
+// Mac is special.
+#ifdef __APPLE__
+typedef __sanitizer::u64 OFF_T;
+#else
 typedef __sanitizer::uptr OFF_T;
+#endif
 typedef __sanitizer::u64  OFF64_T;
 
 // How to add an interceptor: