patches to build on freebsd 12

- added cc and ar scripts for freebsd12.amd64
- fix for sfio macro SF_FLAGS also being defined for sendfile(2) in socket.h
-- fix is to hide the sendfile(2) macro
- defined _STDFILE_DECLARED to handle FILE macro incompatibility
- added test in std/features/procfs to deal with freebsd kvm interface
-- being different from what AST expects (for ps.c)
- fix for std/banner.c to clean up main() definition
- changed comment in ar.* scripts to match cc.* scripts

src/lib/libast/features/sfio

@@ -4,6 +4,8 @@ sys	filio,ioctl
 lib	qfrexp,qldexp
 key	signed
 
+typ	struct.sf_hdtr sys/socket.h
+
 tst	- note{ number of bits in pointer }end output{
 	#include <stdio.h>
 	int

src/lib/libast/features/wchar

@@ -6,6 +6,9 @@ set	include .
 cat{
 	#ifndef _AST_WCHAR_H
 	#define _AST_WCHAR_H	1
+	#ifdef __FreeBSD__
+	#define _STDFILE_DECLARED 1
+	#endif
 }end
 
 lib	mbstowcs,wctomb,wcrtomb,wcslen,wcstombs,wcwidth stdlib.h stdio.h wchar.h