Fix compliation error in AIX7: conflicting types for 'getargs'

The compilation error in AIX7:

      CC     processes.lo
    processes.c:226:5: error: conflicting types for 'getargs'
     int getargs (struct procentry64 *processBuffer, int bufferLen, char *argsBuffer, int argsLen);
     ^
    In file included from processes.c:106:0:
    /usr/include/procinfo.h:1093:17: note: previous declaration of 'getargs' was here
     extern  int     getargs( void *, int, char *, int );

In AIX6 getargs was not declared but in AIX7 the declaration was added in procinfo.h.

Change the declaration of ``getargs`` to match the declaration in AIX7.