This is in preparation for using Gnulib regex for etags,
to avoid collisions in include directives.
* src/regex-emacs.c: Rename from src/regex.c.
* src/regex-emacs.h: Rename from src/regex.h.  All uses changed.
* test/src/regex-emacs-tests.el: Rename from test/src/regex-tests.el.

* src/lisp.h (compile_pattern): Remove prototype of
now-internal function.

* src/regex.c (POS_AS_IN_BUFFER): Consult gl_state instead of
re_match_object: the latter can change in Lisp.
(re_match_2_internal): Switch back to UPDATE_SYNTAX_* FROM
UPDATE_SYNTAX_FAST*, allowing calls into Lisp.

* src/regex.h (re_match_object): Uncomment declaration.

* src/search.c (struct regexp_cache): Add `busy' field.
(thaw_buffer_relocation): Delete; rely on unbind.
(compile_pattern_1): Assert pattern isn't busy.
(shrink_regexp_cache): Don't shrink busy patterns.
(clear_regexp_cache): Don't nuke busy patterns.
(unfreeze_pattern, freeze_pattern): New functions.
(compile_pattern): Return a regexp_cache pointer instead of the
re_pattern_buffer, allowing callers to use `freeze_pattern' if
needed.  Do not consider busy patterns as cache hit candidates;
error if we run out of non-busy cache entries.
(looking_at_1, fast_looking_at): Snapshot
Vinhibit_changing_match_data; mark pattern busy while we're
matching it; unbind.
(string_match_1, fast_string_match_internal)
(fast_c_string_match_ignore_case): Adjust for compile_pattern
return type.
(search_buffer_re): Regex code from old search_buffer moved here;
snapshot Vinhibit_changing_match_data; mark pattern busy while
we're matching it; unbind.
(search_buffer_non_re): Non-regex code from old search_buffer
moved here.
(search_buffer): Split into search_buffer_re,
search_buffer_non_re.
(syms_of_search): Staticpro re_match_object, even though we really
shouldn't have to.

* src/syntax.h (UPDATE_SYNTAX_TABLE_FORWARD_FAST):
(UPDATE_SYNTAX_TABLE_FAST): Remove.

* src/thread.h (struct thread_state): Remove m_re_match_object,
which is global again.  (It never needs to be preserved across
thread switch.)

* src/regex.h (struct re_pattern_buffer): Reorder charset_unibyte
field to keep bitfields together.

* src/regex.h (RE_DUP_MAX): Raise limit to 2^16-1.
* etc/NEWS: Announce it.
* doc/lispref/searching.texi (Regexp Backslash): Document it.
* test/src/regex-tests.el (regex-repeat-limit): Test it.

* src/regex.h (reg_errcode_t): Add REG_ESIZEBR code.
* src/regex.c (re_error_msgid): Add corresponding entry.
(GET_INTERVAL_COUNT): Return it instead of the more generic REG_EBADBR
when encountering a repetition greater than RE_DUP_MAX.

* lisp/isearch.el (isearch-search): Don't convert errors starting with
"Invalid" into "incomplete".  Such errors are not incomplete, in the
sense that they cannot be corrected by appending more characters to
the end of the regexp.  The affected error messages are:

- REG_BADPAT "Invalid regular expression"
  - \\(?X:\\) where X is not a legal group number
  - \\_X where X is not < or >

- REG_ECOLLATE "Invalid collation character"
  - There is no code to throw this.

- REG_ECTYPE "Invalid character class name"
  - [[:foo:] where foo is not a valid class name

- REG_ESUBREG "Invalid back reference"
  - \N where N is referenced before matching group N

- REG_BADBR "Invalid content of \\{\\}"
  - \\{N,M\\} where N < 0, M < N, M or N larger than max
  - \\{NX where X is not a digit or backslash
  - \\{N\\X where X is not a }

- REG_ERANGE "Invalid range end"
  - There is no code to throw this.

- REG_BADRPT "Invalid preceding regular expression"
  - We never throw this.  It would usually indicate a "*" with no
    preceding regexp text, but Emacs allows that to match a literal
    "*".

Run admin/update-copyright.

Most of this change is to boilerplate commentary such as license URLs.
This change was prompted by ftp://ftp.gnu.org's going-away party,
planned for November.  Change these FTP URLs to https://ftp.gnu.org
instead.  Make similar changes for URLs to other organizations moving
away from FTP.  Also, change HTTP to HTTPS for URLs to gnu.org and
fsf.org when this works, as this will further help defend against
man-in-the-middle attacks (for this part I omitted the MS-DOS and
MS-Windows sources and the test tarballs to keep the workload down).
HTTPS is not fully working to lists.gnu.org so I left those URLs alone
for now.

* src/regex.h:
* src/regex.c (re_wctype_parse): Don't use non-ASCII quotes in
comments.

While the stack is increased in main(), to allow the regex stack
allocation to use alloca we also need to modify regex.c to actually take
advantage of the increased stack, and not limit stack allocations to
SAFE_ALLOCA bytes.

* src/regex.c (MATCH_MAY_ALLOCATE): Remove obsolete comment about
allocations in signal handlers which no longer happens and correct
description about when and why MATCH_MAY_ALLOCATE should be defined.
(emacs_re_safe_alloca): New variable.
(REGEX_USE_SAFE_ALLOCA): Use it as the limit of stack allocation instead
of MAX_ALLOCA.
(emacs_re_max_failures): Rename from `re_max_failures' to avoid
confusion with glibc's `re_max_failures'.
* src/emacs.c (main): Increase the amount of fixed 'extra' bytes we add
to the stack.  Instead of changing emacs_re_max_failures based on the
new stack size, just change emacs_re_safe_alloca; emacs_re_max_failures
remains constant regardless, since if we run out stack space SAFE_ALLOCA
will fall back to heap allocation.

Co-authored-by: Eli Zaretskii <eliz@gnu.org>

2e2a806 Fix copyright years by hand
5badc81 Update copyright year to 2017

Run admin/update-copyright.