Build & getconf fixes for macOS (and UnixWare)

src/lib/libast/features/standards:
- Add heuristic (u_long availability) for systems that hide rather
  than reveal functionality in the presence of _POSIX_SOURCE, etc.
- Define _DARWIN_C_SOURCE, like _GNU_SOURCE, to enable the full
  range of definitions on macOS systems.
- Due to the above, remove MACH (macOS)-specific hack.
- These changes ported from https://github.com/att/ast/pull/1492 -
  thanks to Lev Kujawski (@lkujaw). His PR indicates that this
  fixes the standards macros on UnixWare, too. Therefore, no longer
  exclude UnixWare from standards macros (re: ff70c27f).

src/lib/libast/comp/conf.sh:
- Promote the 'op' member in Conf_t (struct Conf_s) from short to
  int. This allows some Darwin/macOS values, now exposed, to fit
  that would otherwise be truncated, namely:
  _CS_DARWIN_USER_CACHE_DIR               65538
  _CS_DARWIN_USER_DIR                     65536
  _CS_DARWIN_USER_TEMP_DIR                65537
  Thus, the following AST getconf values are now correct on macOS:
  $ /opt/ast/bin/getconf | grep ^DARWIN
  DARWIN_USER_CACHE_DIR=/var/folders/nx/(REDACTED)/C/
  DARWIN_USER_DIR=/var/folders/nx/(REDACTED)/0/
  DARWIN_USER_TEMP_DIR=/var/folders/nx/(REDACTED)/T/

src/lib/libast/features/tty:
- Include <sys/ioctl.h> if available. This silences a compiler
  warning in src/lib/libast/misc/procopen.c about an invalid
  implicit declaration of ioctl(2).

src/lib/libast/comp/conf.sh

@@ -1546,7 +1546,7 @@ struct Conf_s
 	short		standard;
 	short		section;
 	short		call;
-	short		op;
+	int		op;
 };
 
 typedef struct Prefix_s

src/lib/libast/features/standards

@@ -1,29 +1,39 @@
 set stdio
+
+# Flag systems that omit necessary definitions such as u_long
+# when _POSIX_SOURCE or _XOPEN_SOURCE are defined.
+# Affected: Mac OS X, UnixWare.
+typ u_long
+
 # In FreeBSD, definitions like _POSIX_SOURCE and such are used to *limit*
 # functionality to known API; they don't enable anything. The general intent in
-# BSD is to enable everything by default (effectively, providing the
+# BSD is to enable everything by default. So we look for that here, but stay
-# _KITCHEN_SINK_SOURCE mentioned below). So we look for that here, but stay
 # careful that we don't get fooled by presence of FreeBSD that underpins some
 # subsystems in Mac OS X; there are other Apple-specific portability hacks
 # elsewhere we should not interfere with.
-if tst note{ FreeBSD, DragonFly BSD, or UnixWare }end compile{
+if tst note{ FreeBSD or DragonFly BSD }end compile{
 		#include <sys/param.h>
-		#if (!defined(__FreeBSD__) && !defined(__DragonFly__) && !defined(__USLC__)) || defined(APPLE)
+		#if (!defined(__FreeBSD__) && !defined(__DragonFly__)) || defined(__APPLE__) || defined(__MACH__)
-		#error not a FreeBSD or DragonFly BSD system
+		#error not one of the listed systems
 		#endif
 	}end {
 	}
-elif tst note{ _ALL_SOURCE & _POSIX_SOURCE & _POSIX_C_SOURCE & _XOPEN_SOURCE & __EXTENSIONS__ works }end compile{
+elif tst note{ _ALL_SOURCE & _POSIX_SOURCE & _POSIX_C_SOURCE & _XOPEN_SOURCE & _GNU_SOURCE & _DARWIN_C_SOURCE & __EXTENSIONS__ works }end compile{
 		#define _ALL_SOURCE	1
 		#define _POSIX_SOURCE	1
 		#define _POSIX_C_SOURCE	21000101L
 		#define _XOPEN_SOURCE	9900
 		#define _GNU_SOURCE	1
+		#define _DARWIN_C_SOURCE 1
 		#define __EXTENSIONS__	1
 		#include <sys/types.h>
 		#include <sys/stat.h>
 		#include <stdlib.h>
 		#include <unistd.h>
+		#include <fcntl.h>
+		#if _typ_u_long
+		u_long _test_dummy_;
+		#endif
 	}end {
 		#ifndef _ALL_SOURCE
 		#define _ALL_SOURCE	1
@@ -40,20 +50,28 @@ elif tst note{ _ALL_SOURCE & _POSIX_SOURCE & _POSIX_C_SOURCE & _XOPEN_SOURCE & _
 		#ifndef _GNU_SOURCE
 		#define _GNU_SOURCE	1
 		#endif
+		#ifndef _DARWIN_C_SOURCE
+		#define _DARWIN_C_SOURCE 1
+		#endif
 		#ifndef __EXTENSIONS__
 		#define __EXTENSIONS__	1
 		#endif
 	}
-elif tst note{ _ALL_SOURCE & _POSIX_SOURCE & _XOPEN_SOURCE & __EXTENSIONS__ works }end compile{
+elif tst note{ _ALL_SOURCE & _POSIX_SOURCE & _XOPEN_SOURCE & _GNU_SOURCE & _DARWIN_C_SOURCE & __EXTENSIONS__ works }end compile{
 		#define _ALL_SOURCE	1
 		#define _POSIX_SOURCE	1
 		#define _XOPEN_SOURCE	9900
 		#define _GNU_SOURCE	1
+		#define _DARWIN_C_SOURCE 1
 		#define __EXTENSIONS__	1
 		#include <sys/types.h>
 		#include <sys/stat.h>
 		#include <stdlib.h>
 		#include <unistd.h>
+		#include <fcntl.h>
+		#if _typ_u_long
+		u_long _test_dummy;
+		#endif
 	}end {
 		#ifndef _ALL_SOURCE
 		#define _ALL_SOURCE	1
@@ -67,20 +85,28 @@ elif tst note{ _ALL_SOURCE & _POSIX_SOURCE & _XOPEN_SOURCE & __EXTENSIONS__ work
 		#ifndef _GNU_SOURCE
 		#define _GNU_SOURCE	1
 		#endif
+		#ifndef _DARWIN_C_SOURCE
+		#define _DARWIN_C_SOURCE 1
+		#endif
 		#ifndef __EXTENSIONS__
 		#define __EXTENSIONS__	1
 		#endif
 	}
-elif tst note{ _POSIX_SOURCE & _POSIX_C_SOURCE & _XOPEN_SOURCE & __EXTENSIONS__ works }end compile{
+elif tst note{ _POSIX_SOURCE & _POSIX_C_SOURCE & _XOPEN_SOURCE & _GNU_SOURCE & _DARWIN_C_SOURCE & __EXTENSIONS__ works }end compile{
 		#define _POSIX_SOURCE	1
 		#define _POSIX_C_SOURCE	21000101L
 		#define _XOPEN_SOURCE	9900
 		#define _GNU_SOURCE	1
+		#define _DARWIN_C_SOURCE 1
 		#define __EXTENSIONS__	1
 		#include <sys/types.h>
 		#include <sys/stat.h>
 		#include <stdlib.h>
 		#include <unistd.h>
+		#include <fcntl.h>
+		#if _typ_u_long
+		u_long _test_dummy;
+		#endif
 	}end {
 		#ifndef _POSIX_SOURCE
 		#define _POSIX_SOURCE	1
@@ -94,6 +120,9 @@ elif tst note{ _POSIX_SOURCE & _POSIX_C_SOURCE & _XOPEN_SOURCE & __EXTENSIONS__
 		#ifndef _GNU_SOURCE
 		#define _GNU_SOURCE	1
 		#endif
+		#ifndef _DARWIN_C_SOURCE
+		#define _DARWIN_C_SOURCE 1
+		#endif
 		#ifndef __EXTENSIONS__
 		#define __EXTENSIONS__	1
 		#endif
@@ -106,6 +135,10 @@ elif tst note{ _POSIX_SOURCE & _XOPEN_SOURCE & __EXTENSIONS__ works }end compile
 		#include <sys/stat.h>
 		#include <stdlib.h>
 		#include <unistd.h>
+		#include <fcntl.h>
+		#if _typ_u_long
+		u_long _test_dummy;
+		#endif
 	}end {
 		#ifndef _POSIX_SOURCE
 		#define _POSIX_SOURCE	1
@@ -124,6 +157,10 @@ elif tst note{ _XOPEN_SOURCE & __EXTENSIONS__ works }end compile{
 		#include <sys/stat.h>
 		#include <stdlib.h>
 		#include <unistd.h>
+		#include <fcntl.h>
+		#if _typ_u_long
+		u_long _test_dummy;
+		#endif
 	}end {
 		#ifndef _XOPEN_SOURCE
 		#define _XOPEN_SOURCE	1
@@ -138,6 +175,10 @@ elif tst note{ _XOPEN_SOURCE works }end compile{
 		#include <sys/stat.h>
 		#include <stdlib.h>
 		#include <unistd.h>
+		#include <fcntl.h>
+		#if _typ_u_long
+		u_long _test_dummy;
+		#endif
 	}end {
 		#ifndef _XOPEN_SOURCE
 		#define _XOPEN_SOURCE	1
@@ -147,6 +188,10 @@ else tst note{ __EXTENSIONS__ works }end compile{
 		#define __EXTENSIONS__	1
 		#include <sys/types.h>
 		#include <sys/stat.h>
+		#include <fcntl.h>
+		#if _typ_u_long
+		u_long _test_dummy;
+		#endif
 	}end {
 		#ifndef __EXTENSIONS__
 		#define __EXTENSIONS__	1
@@ -167,19 +212,3 @@ if tst -D_ISOC99_SOURCE -lm note{ _ISOC99_SOURCE plays nice }end link{
 		#endif
 	}
 endif
-
-cat{
-
-/*
- * this is a nasty game we all play to honor standards symbol visibility
- * it would help if all implementations had
- *	_KITCHEN_SINK_SOURCE
- * that enabled all symbols from the latest implemented standards
- * that's probably the most useful but least portable request
- */
-
-#if __MACH__
-#undef  _POSIX_SOURCE
-#endif
-
-}end

src/lib/libast/features/tty

@@ -1,4 +1,4 @@
-hdr	termios,termio,sgtty
+hdr	termios,termio,sgtty,sys/ioctl
 sys	termios,termio,ioctl,bsdtty,nttyio,ttyio
 lib	tcgetattr,tcgetpgrp termios.h
 mac	_POSIX_VDISABLE termios.h
@@ -107,6 +107,10 @@ cat{
 #   endif /* TCSANOW */
 #endif /* _hdr_termios */
 
+#if _hdr_sys_ioctl
+#   include <sys/ioctl.h>
+#endif
+
 /* set ECHOCTL if driver can echo control characters as ^c */
 #ifdef LCTLECH
 #   ifndef ECHOCTL