Fix a compiler error in ptrace.c
Fix a compiler error in ptrace.c

On some systems, including sys/user.h before sys/types.h causes a
compiler error. Changing the order of the #includes fixes the error.

yatsek/reptyr,developerfm/reptyr,nelhage/reptyr,jerome-pouiller/reredirect,developerfm/reptyr,yatsek/reptyr,developerfm/reptyr,nelhage/reptyr,yatsek/reptyr,jerome-pouiller/reredirect,nelhage/reptyr