drm_hwcomposer: Include stdlib.h in the importer

Change-Id: I3fffc5e62c07de9561b6f998700a98862ebd5fc8
Signed-off-by: Sean Paul <seanpaul@chromium.org>
diff --git a/hwcomposer_import_drm_gralloc.cpp b/hwcomposer_import_drm_gralloc.cpp
index 065170c..1e54f70 100644
--- a/hwcomposer_import_drm_gralloc.cpp
+++ b/hwcomposer_import_drm_gralloc.cpp
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+#include <stdlib.h>
 
 #include <cutils/log.h>