Fix more compiler warnings, typos and other minor issues (#260)

Many of these changes are minor typo fixes. The other changes
(which are mostly compiler warning fixes) are:

NEWS:
- The --globcasedetect shell option works on older Linux kernels
  when used with FAT32/VFAT file systems, so remove the note about
  it only working with 5.2+ kernels.

src/cmd/ksh93/COMPATIBILITY:
- Update the documentation on function scoping with an addition
  from ksh93v- (this does apply to ksh93u+).

src/cmd/ksh93/edit/emacs.c:
- Check for '_AST_ksh_release', not 'AST_ksh_release'.

src/cmd/INIT/mamake.c,
src/cmd/INIT/ratz.c,
src/cmd/INIT/release.c,
src/cmd/builtin/pty.c:
- Add more uses of UNREACHABLE() and noreturn, this time for the
  build system and pty.

src/cmd/builtin/pty.c,
src/cmd/builtin/array.c,
src/cmd/ksh93/sh/name.c,
src/cmd/ksh93/sh/nvtype.c,
src/cmd/ksh93/sh/suid_exec.c:
- Fix six -Wunused-variable warnings (the name.c nv_arrayptr()
  fixes are also in ksh93v-).
- Remove the unused 'tableval' function to fix a -Wunused-function
  warning.

src/cmd/ksh93/sh/lex.c:
- Remove unused 'SHOPT_DOS' code, which isn't enabled anywhere.
  https://github.com/att/ast/issues/272#issuecomment-354363112

src/cmd/ksh93/bltins/misc.c,
src/cmd/ksh93/bltins/trap.c,
src/cmd/ksh93/bltins/typeset.c:
- Add dictionary generator function declarations for former
  aliases that are now builtins (re: 1fbbeaa1, ef1621c1, 3ba4900e).
- For consistency with the rest of the codebase, use '(void)'
  instead of '()' for print_cpu_times.

src/cmd/ksh93/sh/init.c,
src/lib/libast/path/pathshell.c:
- Move the otherwise unused EXE macro to pathshell() and only
  search for 'sh.exe' on Windows.

src/cmd/ksh93/sh/xec.c,
src/lib/libast/include/ast.h:
- Add an empty definition for inline when compiling with C89.
  This allows the timeval_to_double() function to be inlined.

src/cmd/ksh93/include/shlex.h:
- Remove the unused 'PIPESYM2' macro.

src/cmd/ksh93/tests/pty.sh:
- Add '# err_exit #' to count the regression test added in
  commit 113a9392.

src/lib/libast/disc/sfdcdio.c:
- Move diordwr, dioread, diowrite and dioexcept behind
  '#ifdef F_DIOINFO' to fix one -Wunused-variable warning and
  multiple -Wunused-function warnings (sfdcdio() only uses these
  functions when F_DIOINFO is defined).

src/lib/libast/string/fmtdev.c:
- Fix two -Wimplicit-function-declaration warnings on Linux by
  including sys/sysmacros.h in fmtdev().

src/cmd/ksh93/sh/lex.c

@@ -19,7 +19,7 @@
 ***********************************************************************/
 #pragma prototyped
 /*
- * KornShell  lexical analyzer
+ * KornShell lexical analyzer
  *
  * Written by David Korn
  * AT&T Labs
@@ -73,7 +73,7 @@ local_iswblank(wchar_t wc)
 struct lexstate
 {
 	char		incase;		/* 1 for case pattern, 2 after case */
-	char		intest;		/* 1 inside [[...]] */
+	char		intest;		/* 1 inside [[ ... ]] */
 	char		testop1;	/* 1 when unary test op legal */
 	char		testop2;	/* 1 when binary test op legal */
 	char		reservok;	/* >0 for reserved word legal */
@@ -758,7 +758,7 @@ int sh_lex(Lex_t* lp)
 				mode = ST_NORM;
 				continue;
 			case S_LIT:
-				if(oldmode(lp)==ST_NONE && !lp->lexd.noarg)	/*  in ((...)) */
+				if(oldmode(lp)==ST_NONE && !lp->lexd.noarg)	/* in ((...)) */
 				{
 					if((c=fcpeek(0))==LPAREN || c==RPAREN || c=='$' || c==LBRACE || c==RBRACE || c=='[' || c==']')
 					{
@@ -813,7 +813,7 @@ int sh_lex(Lex_t* lp)
 					ingrave = !ingrave;
 				/* FALLTHROUGH */
 			case S_QUOTE:
-				if(oldmode(lp)==ST_NONE && lp->lexd.arith)	/*  in ((...)) */
+				if(oldmode(lp)==ST_NONE && lp->lexd.arith)	/* in ((...)) */
 				{
 					if(n!=S_GRAVE || fcpeek(0)=='\'')
 						continue;
@@ -2321,10 +2321,6 @@ struct argnod *sh_endword(Shell_t *shp,int mode)
 				break;
 			}
 			n = *sp;
-#if SHOPT_DOS
-			if(!(inquote&1) && sh_lexstates[ST_NORM][n]==0)
-				break;
-#endif /* SHOPT_DOS */
 			if(!(inquote&1) || (sh_lexstates[ST_QUOTE][n] && n!=RBRACE))
 			{
 				if(n=='\n')