art: -Wsystem-header warning

- TEMP_FAILURE_RETRY redefined if unistd.h is include later

Change-Id: I79101ebfbec47e7854414c4ef40a91ef122ae284
diff --git a/runtime/base/macros.h b/runtime/base/macros.h
index 47571f8..fe5a2ef 100644
--- a/runtime/base/macros.h
+++ b/runtime/base/macros.h
@@ -18,6 +18,17 @@
 #define ART_RUNTIME_BASE_MACROS_H_
 
 #include <stddef.h>  // for size_t
+#include <unistd.h>  // for TEMP_FAILURE_RETRY
+
+// bionic and glibc both have TEMP_FAILURE_RETRY, but eg Mac OS' libc doesn't.
+#ifndef TEMP_FAILURE_RETRY
+#define TEMP_FAILURE_RETRY(exp) ({ \
+  decltype(exp) _rc; \
+  do { \
+    _rc = (exp); \
+  } while (_rc == -1 && errno == EINTR); \
+  _rc; })
+#endif
 
 #define GCC_VERSION (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
 
@@ -166,16 +177,6 @@
 
 #define PURE __attribute__ ((__pure__))
 
-// bionic and glibc both have TEMP_FAILURE_RETRY, but Mac OS' libc doesn't.
-#ifndef TEMP_FAILURE_RETRY
-#define TEMP_FAILURE_RETRY(exp) ({ \
-  decltype(exp) _rc; \
-  do { \
-    _rc = (exp); \
-  } while (_rc == -1 && errno == EINTR); \
-  _rc; })
-#endif
-
 template<typename T> void UNUSED(const T&) {}
 
 // Annotalysis thread-safety analysis support.