MD5 removal of int64 code

I have applied the following patch to remove MD5 usage of int64 types.
I split it into two int32 values and did the job that way. I also
changed the code to use standard c.h data types, and changes 0xFF to
0xff.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026