vchoi_fork

[svn-r2947] Purpose:
    Code optimization
Description:
    Re-vamped FUNC_ENTER macro to remove as many of the if's as possible and
    also to only check once if any given function is an API function.

    This improves the performance of the hyperslab I/O benchmark (h5hypers)
    that I've been testing with by another 5%.  All library functions should
    be 5-15% faster, depending on how many times they are called and what
    percentage of the function's time was spent in the FUNC_ENTER macro vs.
    the percentage of time in the main body of the function.
Platforms tested:
    Solaris 2.6 (baldric)