Merge from upstream, upto version 5.22.

Merge from upstream, upto version 5.22.
After 5.0:
 `cperl-add-tags-recurse-noxs-fullpath': new function (for -batch mode)

After 5.1:
;; Major edit.  Summary of most visible changes:

;; a) Multiple <<HERE per line allowed.
;; b) Handles multiline subroutine declaration headers (with comments).
;;    (The exception is `cperl-etags' - but it is not used in the rest
;;    of the mode.)
;; c) Fontifies multiline my/our declarations (even with comments,
;;    and with legacy `font-lock').
;; d) Major speedup of syntaxification, both immediate and postponed
;;    (3.5x to 15x [for different CPUs and versions of Emacs] on the
;;    huge real-life document I tested).
;; e) New bindings, edits to imenu.
;; f) "_" is made into word-char during fontification/syntaxification;
;;    some attempts to recognize non-word "_" during other operations too.
;; g) Detect bug in Emacs with `looking-at' inside `narrow' and bulk out.
;; h) autoload some more perldoc-related stuff
;; i) Some new convenience features: ISpell POD/HEREDOCs, narrow-to-HEREDOC
;; j) Attempt to incorporate XEmacs edits which reached me

Fine-grained changelog:
`cperl-hook-after-change':	New configuration variable
`cperl-vc-sccs-header':	Likewise.
`cperl-vc-sccs-header':	Likewise.
`cperl-vc-header-alist':	Default via two preceding variables
`cperl-invalid-face':	Remove double quoting under XEmacs
				(still needed under 21.2)
`cperl-tips':		Update URLs for resources
`cperl-problems':		Likewise.
`cperl-praise':		Mention new features
New C-c key bindings:	for `cperl-find-bad-style',
`cperl-pod-spell', `cperl-here-doc-spell', `cperl-narrow-to-here-doc',
`cperl-perdoc', `cperl-perldoc-at-point'
CPerl Mode menu changes:	"Fix style by spaces", "Imenu on Perl Info"
moved, new submenu of Tools with Ispell entries and narrowing.
`cperl-after-sub-regexp':	New defsubst
`cperl-imenu--function-name-regexp-perl': Use `cperl-after-sub-regexp',
			Allows heads up to head4
			Allow "package;"
`defun-prompt-regexp':	Use `cperl-after-sub-regexp',
`paren-backwards-message':	??? Something for XEmacs???
`cperl-mode':		Never auto-switch abbrev-mode off
			Try to allow '_' be non-word char
			Do not use `font-lock-unfontify-region-function' on XEmacs
			Reset syntax cache on mode start
			Support multiline facification (even
			        on legacy `font-lock')
`cperl-facemenu-add-face-function':	??? Some contributed code ???
`cperl-after-change-function':	Since `font-lock' and `lazy-lock'
        refuse to inform us whether the fontification is due to lazy
        calling or due to edit to a buffer, install our own hook
        (controlled by `cperl-hook-after-change')
`cperl-electric-pod':	=cut may have been recognized as start
`cperl-block-p':		Moved, updated for attributes
`cperl-calculate-indent':	Try to allow '_' be non-word char
			Support subs with attributes
`cperl-where-am-i':		Queit (?) a warning
`cperl-cached-syntax-table'	New function
`cperl-forward-re':		Use `cperl-cached-syntax-table'
`cperl-unwind-to-safe':	Recognize `syntax-type' property
				changing in a middle of line
`cperl-find-sub-attrs':	New function
`cperl-find-pods-heres':	Allow many <<EOP per line
			Allow subs with attributes
			Major speedups (3.5x..15x on a real-life
			        test file nph-proxy.pl)
			Recognize "extproc " (OS/2)
			        case-folded and only at start
			/x on s///x with empty replacement was
			        not recognized
			Better comments
`cperl-after-block-p':	Remarks on diff with `cperl-block-p'
			Allow subs with attributes, labels
			Do not confuse "else::foo" with "else"
			Minor optimizations...
`cperl-after-expr-p':	Try to allow '_' be non-word char
`cperl-fill-paragraph':	Try to detect a major bug in Emacs
        with `looking-at' inside `narrow' and bulk out if found
`cperl-imenu--create-perl-index':	Updates for new
        `cperl-imenu--function-name-regexp-perl'
`cperl-outline-level':	Likewise.
`cperl-init-faces':		Allow multiline subroutine headers
        and my/our declarations, and ones with comments
			Allow subroutine attributes
`cperl-imenu-on-info':	Better docstring.
`cperl-etags'		Rudimentary support for attributes
			Support for packages and "package;"
`cperl-add-tags-recurse-noxs':	Better (?) docstring
`cperl-add-tags-recurse-noxs-fullpath': Likewise.
`cperl-tags-hier-init':	Misprint for `fboundp' fixed
`cperl-not-bad-style-regexp':	Try to allow '_' be non-word char
`cperl-perldoc':		Add autoload
`cperl-perldoc-at-point':	Likewise.
`cperl-here-doc-spell':	New function
`cperl-pod-spell':		Likewise.
`cperl-map-pods-heres':	Likewise.
`cperl-get-here-doc-region':	Likewise.
`cperl-font-lock-fontify-region-function': Likewise (backward compatibility
				        for legacy `font-lock')
`cperl-font-lock-unfontify-region-function': Fix style
`cperl-fontify-syntaxically':	Recognize and optimize away
        deferred calls with no-change.  Governed by `cperl-hook-after-change'
`cperl-fontify-update':	Recognize that syntaxification region
        can be larger than fontification one.
        XXXX we leave `cperl-postpone' property, so this is quadratic...
`cperl-fontify-update-bad':	Temporary placeholder until
        it is clear how to implement `cperl-fontify-update'.
`cperl-time-fontification':	New function
`attrib-group':		New text attribute
`multiline':		New value: `syntax-type' text attribute

After 5.2:
`cperl-emulate-lazy-lock':	New function
`cperl-fontify-syntaxically': Would skip large regions
Add `cperl-time-fontification', `cperl-emulate-lazy-lock' to menu
Some globals were declared, but uninitialized

After 5.3, 5.4:
`cperl-facemenu-add-face-function':	Add docs, fix U<>
Copyright message updated.
`cperl-init-faces':		Work around a bug in `font-lock'. May slow
				facification down a bit.
			Misprint for my|our|local for old `font-lock'
			"our" was not fontified same as "my|local"
			Highlight variables after "my" etc even in
				a middle of an expression
			Do not facify multiple variables after my etc
				unless parentheses are present

After 5.5, 5.6
`cperl-fontify-syntaxically': after-change hook could reset
`cperl-syntax-done-to' to a middle of line; unwind to BOL.

After 5.7:
`cperl-init-faces':		Allow highlighting of local ($/)
`cperl-problems-old-emaxen': New variable (for the purpose of DOCSTRING).
`cperl-problems':		Remove fixed problems.
`cperl-find-pods-heres':	Recognize #-comments in m##x too
			Recognize charclasses (unless delimiter is \).
`cperl-fontify-syntaxically': Unwinding to safe was done in wrong order
`cperl-regexp-scan':	Update docs
`cperl-beautify-regexp-piece': use information got from regexp scan

After 5.8:
Major user visible changes:
Recognition and fontification of character classes in RExen.
Variable indentation of RExen according to groups

`cperl-find-pods-heres':	Recognize POSIX classes in REx charclasses
			Fontify REx charclasses in variable-name face
			Fontify POSIX charclasses in "type" face
			Fontify unmatched "]" in function-name face
			Mark first-char of HERE-doc as `front-sticky'
			Reset `front-sticky' property when needed
`cperl-calculate-indent':	Indents //x -RExen accordning to parens level
`cperl-to-comment-or-eol':	Recognize ends of `syntax-type' constructs
`cperl-backward-to-noncomment': Recognize stringy `syntax-type' constructs
			Support `narrow'ed buffers.
`cperl-praise':		Remove a reservation
`cperl-make-indent':	New function
`cperl-indent-for-comment':	Use `cperl-make-indent'
`cperl-indent-line':	Likewise.
`cperl-lineup':		Likewise.
`cperl-beautify-regexp-piece': Likewise.
`cperl-contract-level':	Likewise.
`cperl-toggle-set-debug-unwind': New function
			New menu entry for this
`fill-paragraph-function':	Use when `boundp'
`cperl-calculate-indent':	Take into account groups when indenting RExen
`cperl-to-comment-or-eol':	Recognize # which end a string
`cperl-modify-syntax-type':	Make only syntax-table property non-sticky
`cperl-fill-paragraph':	Return t: needed for `fill-paragraph-function'
`cperl-fontify-syntaxically': More clear debugging message
`cperl-pod2man-build-command': XEmacs portability: check `Man-filter-list'
`cperl-init-faces':		More complicated highlight even on XEmacs (new)
Merge cosmetic changes from XEmacs

After 5.9:
`cperl-1+':			Moved to before the first use
`cperl-1-':			Likewise.

After 5.10:

This code may lock Emacs hard!!!  Use on your own risk!

`cperl-font-locking':	New internal variable
`cperl-beginning-of-property': New function
`cperl-calculate-indent':	Use `cperl-beginning-of-property'
instead of `previous-single-property-change'
`cperl-unwind-to-safe':	Likewise.
`cperl-after-expr-p':	Likewise.
`cperl-get-here-doc-region': Likewise.
`cperl-font-lock-fontify-region-function': Likewise.
`cperl-to-comment-or-eol':	Do not call `cperl-update-syntaxification'
				recursively
			Bound `next-single-property-change'
				via `point-max'
`cperl-unwind-to-safe':	Bound likewise
`cperl-font-lock-fontify-region-function': Likewise.
`cperl-find-pods-heres':	Mark as recursive for `cperl-to-comment-or-eol'
			Initialization of
`cperl-font-lock-multiline-start' could be missed if the "main"
fontification did not run due to the keyword being already fontified.
`cperl-pod-spell':		Return t from do-one-chunk function
`cperl-map-pods-heres':	Stop when the worker returns nil
			Call `cperl-update-syntaxification'
`cperl-get-here-doc-region': Call `cperl-update-syntaxification'
`cperl-get-here-doc-delim':	Remove unused function

After 5.11:

 The possible lockup of Emacs (introduced in 5.10) fixed

`cperl-unwind-to-safe':	`cperl-beginning-of-property' won't return nil
`cperl-syntaxify-for-menu':	New customization variable
`cperl-select-this-pod-or-here-doc': New function
`cperl-get-here-doc-region': Extra argument
			Do not adjust pos by 1

New menu entries (Perl/Tools): Selection of current POD or HERE-DOC section
			(Debugging CPerl:) backtrace on fontification

After 5.12:
`cperl-cached-syntax-table': use `car-safe'
`cperl-forward-re':		Remove spurious argument SET-ST
			Add documentation
`cperl-forward-group-in-re': New function
`cperl-find-pods-heres':	Find and highlight (?{}) blocks in RExen
(XXXX Temporary (?) hack is to syntax-mark them as comment)

After 5.13:
`cperl-string-syntax-table': Make { and } not-grouping
  (Sometimes they ARE grouping in RExen, but matching them would only
   confuse in many situations when they are not)
`beginning-of-buffer':	Replaced two occurences with goto-char...
`cperl-calculate-indent':	`char-after' could be nil...
`cperl-find-pods-heres':	REx can start after "[" too
			Hightlight (??{}) in RExen too
`cperl-maybe-white-and-comment-rex': New constant
`cperl-white-and-comment-rex': Likewise.
			XXXX Not very efficient, but hard to make
			better while keeping 1 group

After 5.13:
`cperl-find-pods-heres':	$foo << identifier() is not a HERE-DOC
			Likewise for 1 << identifier

After 5.14:
`cperl-find-pods-heres':	Different logic for $foo .= <<EOF etc
			Error-less condition-case could fail
`cperl-font-lock-fontify-region-function': Likewise.
`cperl-init-faces':		Likewise.

After 5.15:
`cperl-find-pods-heres':	Support property REx-part2
`cperl-calculate-indent':	Likewise.
			Don't special-case REx with non-empty 1st line
`cperl-find-pods-heres':	In RExen, highlight non-literal backslashes
			Invert highlighting of charclasses:
				now the envelop is highlighted
			Highlight many others 0-length builtins
`cperl-praise':		Mention indenting and highlight in RExen

After 5.15:
`cperl-find-pods-heres':	Highlight capturing parens in REx

After 5.16:
`cperl-find-pods-heres':	Highlight '|' for alternation
Initialize `font-lock-warning-face' if not present
`cperl-find-pods-heres':	Use `font-lock-warning-face' instead of
				 `font-lock-function-name-face'
`cperl-look-at-leading-count': Likewise.
`cperl-find-pods-heres':	localize `font-lock-variable-name-face'
				`font-lock-keyword-face' (needed for
				batch processing) etc
			Use `font-lock-builtin-face' for builtin in REx
				Now `font-lock-variable-name-face'
				is used for interpolated variables
			Use "talking aliases" for faces inside REx
			Highlight parts of REx (except in charclasses)
				according to the syntax and/or semantic
			Syntax-mark a {}-part of (?{}) as "comment"
				(it was the ()-part)
			Better logic to distinguish what is what in REx
`cperl-tips-faces':		Document REx highlighting
`cperl-praise':		Mention REx syntax highlight etc.

After 5.17:
`cperl-find-sub-attrs':	Would not always manage to print error message
`cperl-find-pods-heres':	localize `font-lock-constant-face'

After 5.18:
`cperl-find-pods-heres':	Misprint in REx for parsing REx
			Very minor optimization
			`my-cperl-REx-modifiers-face' got quoted
			Recognize "print $foo <<END" as HERE-doc
			Put `REx-interpolated' text attribute if needed
`cperl-invert-if-unless-modifiers':	New function
`cperl-backward-to-start-of-expr': Likewise.
`cperl-forward-to-end-of-expr': Likewise.
`cperl-invert-if-unless':	Works in "the opposite way" too
			Cursor position on return is on the switch-word
			Indents comments better
`REx-interpolated':		New text attribute
`cperl-next-interpolated-REx': New function
`cperl-next-interpolated-REx-0': Likewise.
`cperl-next-interpolated-REx-1': Likewise.
"\C-c\C-x", "\C-c\C-y", "\C-c\C-v":	New keybinding for these functions
Perl/Regexp menu:		3 new entries for `cperl-next-interpolated-REx'
`cperl-praise':		Mention finded interpolated RExen

After 5.19:
`cperl-init-faces':		Highlight %$foo, @$foo too
`cperl-short-docs':		Better docs for system, exec
`cperl-find-pods-heres':	Better detect << after print {FH} <<EOF etc.
			Would not find HERE-doc ended by EOF without NL
`cperl-short-docs':		Correct not-doubled \-escapes
start block:		Put some `defvar' for stuff gone from XEmacs

After 5.20:
initial comment:		Extend copyright, fix email address
`cperl-indent-comment-at-column-0': New customization variable
`cperl-comment-indent':	Indentation after $#a would increasy by 1
`cperl-mode':		Make `defun-prompt-regexp' grok BEGIN/END etc
`cperl-find-pods-heres':	Mark CODE of s///e as `syntax-type' `multiline'
`cperl-at-end-of-expr':	Would fail if @BAR=12 follows after ";"
`cperl-init-faces':		If `cperl-highlight-variables-indiscriminately'
				highlight $ in $foo too (UNTESTED)
`cperl-set-style':		Docstring missed some available styles
toplevel:			Menubar/Perl/Indent-Styles had FSF, now K&R
			Change "Current" to "Memorize Current"
`cperl-indent-wrt-brace':	New customization variable; the default is
			as for pre-5.2 version
`cperl-styles-entries':	Keep `cperl-extra-newline-before-brace-multiline'
`cperl-style-alist':	Likewise.
`cperl-fix-line-spacing':	Support `cperl-merge-trailing-else' being nil,
			and `cperl-extra-newline-before-brace' etc
			being t
`cperl-indent-exp':		Plans B and C to find continuation blocks even
			if `cperl-extra-newline-before-brace' is t

After 5.21:
Improve some docstrings concerning indentation.
`cperl-indent-rules-alist':	New variable
`cperl-sniff-for-indent':	New function name
			(separated from `cperl-calculate-indent')
`cperl-calculate-indent':	Separated the sniffer and the indenter;
			uses `cperl-sniff-for-indent' now
`cperl-comment-indent':	Test for `cperl-indent-comment-at-column-0'
			was inverted;
			Support `comment-column' = 0