Use decltype() instead of typeof()

This fixes a build failure on Mac.

Change-Id: Iee73ba990d2494fd925fd237da68cf753709a248
diff --git a/runtime/base/macros.h b/runtime/base/macros.h
index 8175514..47571f8 100644
--- a/runtime/base/macros.h
+++ b/runtime/base/macros.h
@@ -169,7 +169,7 @@
 // bionic and glibc both have TEMP_FAILURE_RETRY, but Mac OS' libc doesn't.
 #ifndef TEMP_FAILURE_RETRY
 #define TEMP_FAILURE_RETRY(exp) ({ \
-  typeof(exp) _rc; \
+  decltype(exp) _rc; \
   do { \
     _rc = (exp); \
   } while (_rc == -1 && errno == EINTR); \