ion: fix header for including in C++ code

Change-Id: I8fc10ac397e60d329a6887f0590d4dba6cbc7545
Signed-off-by: Dima Zavin <dima@android.com>

include/ion/ion.h

@@ -18,8 +18,13 @@
  *  limitations under the License.
  */
 
+#ifndef __SYS_CORE_ION_H
+#define __SYS_CORE_ION_H
+
 #include <linux/ion.h>
 
+__BEGIN_DECLS
+
 int ion_open();
 int ion_close(int fd);
 int ion_alloc(int fd, size_t len, size_t align, unsigned int flags,
@@ -30,3 +35,6 @@ int ion_map(int fd, struct ion_handle *handle, size_t length, int prot,
 int ion_share(int fd, struct ion_handle *handle, int *share_fd);
 int ion_import(int fd, int share_fd, struct ion_handle **handle);
 
+__END_DECLS
+
+#endif /* __SYS_CORE_ION_H */