None.
Controls whether or not implicit time stamps are inserted into an object file.
-qtimestamps
By default, the compiler inserts an implicit time stamp in an object file when it is created. In some cases, comparison tools may not process the information in such binaries properly. Controlling time stamp generation provides a way of avoiding such problems. To omit the time stamp, use the option -qnotimestamps.
This option does not affect time stamps inserted by pragmas and other explicit mechanisms.