Remove SHOPT_BASH; keep &> redir operator, '-o posix' option

On 16 June there was a call for volunteers to fix the bash
compatibility mode; it has never successfully compiled in 93u+.
Since no one showed up, it is now removed due to lack of interest.

A couple of things are kept, which are now globally enabled:

1. The &>file redirection shorthand (for >file 2>&1). As a matter
   of fact, ksh93 already supported this natively, but only while
   running rc/profile/login scripts, and it issued a warning. This
   makse it globally available and removes the warning, bringing
   ksh93 in line with mksh, bash and zsh.

2. The '-o posix' standard compliance option. It is now enabled on
   startup if ksh is invoked as 'sh' or if the POSIXLY_CORRECT
   variable exists in the environment. To begin with, it disables
   the aforementioned &> redirection shorthand. Further compliance
   tweaks will be added in subsequent commits. The differences will
   be fairly minimal as ksh93 is mostly compliant already.

In all changed files, code was removed that was compiled (more
precisely, failed to compile/link) if the SHOPT_BASH preprocessor
identifier was defined. Below are other changes worth mentioning:

src/cmd/ksh93/sh/bash.c,
src/cmd/ksh93/data/bash_pre_rc.sh:
- Removed.

src/cmd/ksh93/data/lexstates.c,
src/cmd/ksh93/include/shlex.h,
src/cmd/ksh93/sh/lex.c:
- Globally enable &> redirection operator if SH_POSIX not active.
- Remove warning that was issued when &> was used in rc scripts.

src/cmd/ksh93/data/options.c,
src/cmd/ksh93/include/defs.h,
src/cmd/ksh93/sh/args.c:
- Keep SH_POSIX option (-o posix).
- Replace SH_TYPE_BASH shell type by SH_TYPE_POSIX.

src/cmd/ksh93/sh/init.c:
- sh_type(): Return SH_TYPE_POSIX shell type if ksh was invoked
  as sh (or rsh, restricted sh).
- sh_init(): Enable posix option if the SH_TYPE_POSIX shell type
  was detected, or if the CONFORMANCE ast config variable was set
  to "standard" (which libast sets on init if POSIXLY_CORRECT
  exists in the environment).

src/cmd/ksh93/tests/options.sh,
src/cmd/ksh93/tests/io.sh:
- Replace regression tests for &> and move to io.sh. Since &> is
  now for general use, no longer test in an rc script, and don't
  check that a warning is issued.

Closes: #9
Progresses: #20

src/cmd/ksh93/include/builtins.h

@@ -58,11 +58,6 @@
 #define SYSDOT		(shgd->bltin_cmds+20)	/* . */
 #define SYSSOURCE	(shgd->bltin_cmds+21)	/* source */
 #define SYSRETURN	(shgd->bltin_cmds+22)	/* return */
-#if SHOPT_BASH
-#   define SYSLOCAL	(shgd->bltin_cmds+23)	/* local */
-#else
-#   define SYSLOCAL	0
-#endif
 
 /* entry point for shell special builtins */
 

src/cmd/ksh93/include/defs.h

@@ -311,7 +311,6 @@ struct shared
 #define SH_COMPLETE	19	/* set for command completion */
 #define SH_INTESTCMD	20	/* set while test/[ command is being run */
 
-#define SH_BASH			41
 #define SH_BRACEEXPAND		42
 #define SH_POSIX		46
 #define SH_MULTILINE    	47
@@ -319,9 +318,7 @@ struct shared
 #define SH_NOPROFILE		78
 #define SH_NOUSRPROFILE		79
 #define SH_LOGIN_SHELL		67
-#define SH_COMMANDLINE		0x100
-#define SH_BASHEXTRA		0x200
-#define SH_BASHOPT		0x400
+#define SH_COMMANDLINE		0x100	/* flag for invocation-only options ('set -o' cannot change them) */
 
 #define SH_ID			"ksh"	/* ksh id */
 #define SH_STD			"sh"	/* standard sh id */
@@ -330,44 +327,11 @@ struct shared
 
 #define SH_TYPE_SH		001
 #define SH_TYPE_KSH		002
-#define SH_TYPE_BASH		004
+#define SH_TYPE_POSIX		004
 #define SH_TYPE_LOGIN		010
 #define SH_TYPE_PROFILE		020
 #define SH_TYPE_RESTRICTED	040
 
-#if SHOPT_BASH
-#   ifndef SHOPT_HISTEXPAND
-#	define SHOPT_HISTEXPAND	1
-#   endif
-/*
- *  define for all the bash options
- */
-#   define SH_CDABLE_VARS	51
-#   define SH_CDSPELL		52
-#   define SH_CHECKHASH		53
-#   define SH_CHECKWINSIZE	54
-#   define SH_CMDHIST		55
-#   define SH_DOTGLOB		56
-#   define SH_EXECFAIL		57
-#   define SH_EXPAND_ALIASES	58
-#   define SH_EXTGLOB		59
-#   define SH_HOSTCOMPLETE	63
-#   define SH_HUPONEXIT		64
-#   define SH_INTERACTIVE_COMM	65
-#   define SH_LITHIST		66
-#   define SH_MAILWARN		68
-#   define SH_NOEMPTYCMDCOMPL	69
-#   define SH_NOCASEGLOB	70
-#   define SH_NULLGLOB		71
-#   define SH_PHYSICAL		45
-#   define SH_PROGCOMP		72
-#   define SH_PROMPTVARS	73
-#   define SH_RESTRICTED2	74
-#   define SH_SHIFT_VERBOSE	75
-#   define SH_SOURCEPATH	76
-#   define SH_XPG_ECHO		77
-#endif
-
 #if SHOPT_HISTEXPAND
 #   define SH_HISTAPPEND	60
 #   define SH_HISTEXPAND	43
@@ -483,7 +447,6 @@ extern const char	e_dict[];
 #define PRINT_VERBOSE	0x01	/* option on|off list		*/
 #define PRINT_ALL	0x02	/* list unset options too	*/
 #define PRINT_NO_HEADER	0x04	/* omit listing header		*/
-#define PRINT_SHOPT	0x08	/* shopt -s|-u			*/
 #define PRINT_TABLE	0x10	/* table of all options		*/
 
 #ifdef SHOPT_STATS

src/cmd/ksh93/include/io.h

@@ -114,15 +114,6 @@ extern const char	e_sysprofile[];
 #if SHOPT_SYSRC
 extern const char	e_sysrc[];
 #endif
-#if SHOPT_BASH
-#if SHOPT_SYSRC
-extern const char	e_bash_sysrc[];
-#endif
-extern const char	e_bash_rc[];
-extern const char	e_bash_login[];
-extern const char	e_bash_logout[];
-extern const char	e_bash_profile[];
-#endif
 extern const char	e_stdprompt[];
 extern const char	e_supprompt[];
 extern const char	e_ambiguous[];

src/cmd/ksh93/include/shlex.h

@@ -41,7 +41,6 @@ typedef struct  _shlex_
 	int		lastline;	/* last line number */
 	int		lasttok;	/* previous token number */
 	int		digits;		/* numerical value with word token */
-	int		nonstandard;	/* nonstandard construct in profile */
 	char		aliasok;	/* on when alias is legal */
 	char		assignok;	/* on when name=value is legal */
 	char		inexec;		/* on when processing exec */

src/cmd/ksh93/include/version.h

@@ -17,4 +17,4 @@
 *                  David Korn <dgk@research.att.com>                   *
 *                                                                      *
 ***********************************************************************/
-#define SH_RELEASE	"93u+m 2020-08-19"
+#define SH_RELEASE	"93u+m 2020-09-01"