support DTrace in the future.

Switch from using DTRACE_PROBEn macros to the dynamically generated macros.
Use "dtrace -h" to create a header file that contains the dynamically
generated macros to be used in the source code instead of the DTRACE_PROBEn
macros.  A dummy header file is generated for builds without DTrace support.

Author: Robert Lor <Robert.Lor@sun.com>