diff --git a/include/cutils/open_memstream.h b/include/cutils/open_memstream.h
index b7998be..c1a81eb 100644
--- a/include/cutils/open_memstream.h
+++ b/include/cutils/open_memstream.h
@@ -19,7 +19,7 @@
 
 #include <stdio.h>
 
-#ifndef HAVE_OPEN_MEMSTREAM
+#if defined(__APPLE__)
 
 #ifdef __cplusplus
 extern "C" {
@@ -31,6 +31,6 @@
 }
 #endif
 
-#endif /*!HAVE_OPEN_MEMSTREAM*/
+#endif /* __APPLE__ */
 
 #endif /*__CUTILS_OPEN_MEMSTREAM_H__*/
diff --git a/libcutils/open_memstream.c b/libcutils/open_memstream.c
index 5b4388a..1c37321 100644
--- a/libcutils/open_memstream.c
+++ b/libcutils/open_memstream.c
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-#ifndef HAVE_OPEN_MEMSTREAM
+#if defined(__APPLE__)
 
 /*
  * Implementation of the POSIX open_memstream() function, which Linux has
@@ -378,4 +378,4 @@
 
 #endif
 
-#endif /*!HAVE_OPEN_MEMSTREAM*/
+#endif /* __APPLE__ */