Add missing include for strerror(3)

Change-Id: I869d4a35e9eafb23a26cc60c98ddcdcd7183296b
diff --git a/ScriptingLayerForAndroid/jni/com_googlecode_android_scripting_Exec.cpp b/ScriptingLayerForAndroid/jni/com_googlecode_android_scripting_Exec.cpp
index cecba3e..cc844a2 100644
--- a/ScriptingLayerForAndroid/jni/com_googlecode_android_scripting_Exec.cpp
+++ b/ScriptingLayerForAndroid/jni/com_googlecode_android_scripting_Exec.cpp
@@ -20,6 +20,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <stdlib.h>
+#include <string.h>
 #include <sys/ioctl.h>
 #include <sys/types.h>
 #include <sys/wait.h>