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/tests/builtins.sh

@@ -226,11 +226,11 @@ if	(( $(printf 'x\0y' | wc -c) != 3 ))
 then	err_exit 'printf \0 not working'
 fi
 if	[[ $(printf "%bx%s\n" 'f\to\cbar') != $'f\to' ]]
-then	err_exit 'printf %bx%s\n  not working'
+then	err_exit 'printf %bx%s\n not working'
 fi
 alpha=abcdefghijklmnop
 if	[[ $(printf "%10.*s\n" 5 $alpha) != '     abcde' ]]
-then	err_exit 'printf %10.%s\n  not working'
+then	err_exit 'printf %10.%s\n not working'
 fi
 float x2=.0000625
 if	[[ $(printf "%10.5E\n" x2) != 6.25000E-05 ]]
@@ -748,11 +748,11 @@ foo=BUG command eval ':'
 # 'whence -f' should ignore functions
 foo_bar() { true; }
 actual="$(whence -f foo_bar)"
-whence -f foo_bar >/dev/null && err_exit "'whence -f' doesn't ignore functions (got '$(printf %q "$actual")')"
+whence -f foo_bar >/dev/null && err_exit "'whence -f' doesn't ignore functions (got $(printf %q "$actual"))"
 
 # whence -vq/type -q must be tested as well
 actual="$(type -f foo_bar 2>&1)"
-type -f foo_bar >/dev/null 2>&1 && err_exit "'type -f' doesn't ignore functions (got '$(printf %q "$actual")')"
+type -f foo_bar >/dev/null 2>&1 && err_exit "'type -f' doesn't ignore functions (got $(printf %q "$actual"))"
 type -qf foo_bar && err_exit "'type -qf' doesn't ignore functions"
 
 # Test the exit status of 'whence -q'
@@ -1060,7 +1060,7 @@ exp=1
 [[ $got == $exp ]] || err_exit "'kill %' has the wrong exit status (expected '$exp'; got '$got')"
 
 # ======
-# 'cd -' should recognize the value of an overriden $OLDPWD variable
+# 'cd -' should recognize the value of an overridden $OLDPWD variable
 # https://github.com/ksh93/ksh/pull/249
 # https://github.com/att/ast/issues/8