Convert default typeset aliases to regular builtins

This converts the 'autoload', 'compound', 'float', 'functions',
'integer' and 'nameref' default aliases into regular built-in
commands, so that 'unalias -a' does not remove them. Shell
functions can now use these names, which improves compatibility
with POSIX shell scripts.

src/cmd/ksh93/data/aliases.c:
- Remove default typeset aliases.

src/cmd/ksh93/data/builtins.c,
src/cmd/ksh93/include/builtins.h:
- Add corresponding built-in command declarations. Typeset-style
  commands are now defined by a pointer range, SYSTYPESET ..
  SYSTYPESET_END. A couple need their own IDs (SYSCOMPOUND,
  SYSNAMEREF) for special-casing in sh/xec.c.
- Update 'typeset --man'.

src/cmd/ksh93/bltins/typeset.c: b_typeset():
- Recognise the new builtin commands by argv[0]. Implement them by
  inserting the corresponding 'typeset' options into the argument
  list before parsing options. This may seem like a bit of a hack,
  but it is simpler, shorter, more future-proof and less
  error-prone than manually copying and adapting all the complex
  flaggery from the option parsing loop.

src/cmd/ksh93/sh/parse.c,
src/cmd/ksh93/sh/xec.c:
- Recognise typeset-style commands by SYSTYPESET .. SYSTYPESET_END
  pointer range.
- Special-case 'compound' (SYSCOMPOUND) and 'nameref' (SYSNAMEREF)
  along with recognising the corresponding 'typeset' options.

src/cmd/ksh93/sh.1:
- Update to document the new built-ins.
- Since not all declaration commands are special built-ins now,
  identify declaration commands using a double-dagger "\(dd"
  character (which renders as '=' in ASCII) and disassociate their
  definition from that of special built-ins.

src/cmd/ksh93/tests/variables.sh:
- Adapt a regression test as there is no more 'integer' alias.

src/cmd/ksh93/include/builtins.h

@@ -41,16 +41,25 @@
 #define SYSCD		(shgd->bltin_cmds+6)	/* cd */
 #define SYSBREAK	(shgd->bltin_cmds+7)	/* break */
 #define SYSCONT		(shgd->bltin_cmds+8)	/* continue */
-#define SYSTYPESET	(shgd->bltin_cmds+9)	/* typeset */
-#define SYSTEST		(shgd->bltin_cmds+10)	/* test */
-#define SYSBRACKET	(shgd->bltin_cmds+11)	/* [ */
-#define SYSLET		(shgd->bltin_cmds+12)	/* let */
-#define SYSEXPORT	(shgd->bltin_cmds+13)	/* export */
-#define SYSDOT		(shgd->bltin_cmds+14)	/* . */
-#define SYSSOURCE	(shgd->bltin_cmds+15)	/* source */
-#define SYSRETURN	(shgd->bltin_cmds+16)	/* return */
+
+#define SYSTYPESET	(shgd->bltin_cmds+9)	/* typeset     \		*/
+						/* autoload	|		*/
+#define SYSCOMPOUND	(shgd->bltin_cmds+11)	/* compound	|		*/
+						/* float	 >typeset range	*/
+						/* functions	|		*/
+						/* integer	|		*/
+#define SYSNAMEREF	(shgd->bltin_cmds+15)	/* nameref      |		*/
+#define SYSTYPESET_END	(shgd->bltin_cmds+15)	/*	       /		*/
+
+#define SYSTEST		(shgd->bltin_cmds+16)	/* test */
+#define SYSBRACKET	(shgd->bltin_cmds+17)	/* [ */
+#define SYSLET		(shgd->bltin_cmds+18)	/* let */
+#define SYSEXPORT	(shgd->bltin_cmds+19)	/* export */
+#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+17)	/* local */
+#   define SYSLOCAL	(shgd->bltin_cmds+23)	/* local */
 #else
 #   define SYSLOCAL	0
 #endif

src/cmd/ksh93/include/version.h

@@ -17,4 +17,4 @@
 *                  David Korn <dgk@research.att.com>                   *
 *                                                                      *
 ***********************************************************************/
-#define SH_RELEASE	"93u+m 2020-07-14"
+#define SH_RELEASE	"93u+m 2020-07-15"