compel: plugins,std -- Include string helpers

They will be needed for log module.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

compel/plugins/include/uapi/plugin-std.h

@@ -3,5 +3,6 @@
 
 #include <compel/plugins.h>
 #include <compel/plugins/std/syscall.h>
+#include <compel/plugins/std/string.h>
 
 #endif /* COMPEL_PLUGIN_STD_STD_H__ */