remove support for non-ANSI compilation

@@ -18,10 +18,11 @@
  *
  * CDDL HEADER END
  */
 
 /*
+ * Copyright 2014 Garrett D'Amore <garrett@damore.org>
  * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2013 by Delphix. All rights reserved.
  */
 
 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */

@@ -504,19 +505,13 @@
         long    sys_rval2;      /* second return value from system call */
 } sysret_t;
 
 #if !defined(_KERNEL)
 
-#if defined(__STDC__)
 extern int      syscall(int, ...);
 extern int      __systemcall(sysret_t *, int, ...);
 extern int      __set_errno(int);
-#else
-extern int      syscall();
-extern int      __systemcall();
-extern int      __set_errno();
-#endif
 
 #endif  /* _KERNEL */
 
 #endif  /* _ASM */