ndb compiler warning, c++ style comment in c-file

#define NDB_TYPE_BIGUNSIGNED            10

#define NDB_TYPE_FLOAT                  11

#define NDB_TYPE_DOUBLE                 12

#define NDB_TYPE_DECIMAL                13      // not used

#define NDB_TYPE_DECIMAL                13      /* not used */

#define NDB_TYPE_CHAR                   14

#define NDB_TYPE_VARCHAR                15

#define NDB_TYPE_BINARY                 16