1 ************************************************************************
2 * Official mandoc TODO.
3 * $Id: TODO,v 1.188 2014/11/20 02:21:27 schwarze Exp $
4 ************************************************************************
6 Many issues are annotated for difficulty as follows:
8 - loc = locality of the issue
9 * single file issue, affects file only, or very few
10 ** single module issue, affects several files of one module
11 *** cross-module issue, significantly impacts multiple modules
12 and may require substantial changes to internal interfaces
13 - exist = difficulty of the existing code in this area
14 * affected code is straightforward and easy to read and change
15 ** affected code is somewhat complex, but once you understand
16 the design, not particularly difficult to understand
17 *** affected code uses a special, exceptionally tricky design
18 - algo = difficulty of the new algorithm to be written
19 * the required logic and code is straightforward
20 ** the required logic is somewhat complex and needs a careful design
21 *** the required logic is exceptionally tricky,
22 maybe an approach to solve that is not even known yet
23 - size = the amount of code to be written or changed
24 * a small number of lines (at most 100, usually much less)
25 ** a considerable amount of code (several dozen to a few hundred)
26 *** a large amount of code (many hundreds, maybe thousands)
27 - imp = importance of the issue
28 * mostly for completeness
29 ** would be nice to have
30 *** issue causes considerable inconvenience
32 Obviously, as the issues have not been solved yet, these annotations
33 are mere guesses, and some may be wrong.
35 ************************************************************************
37 ************************************************************************
39 - The abort() in bufcat(), html.c, can be triggered via buffmt_includes()
40 by running -Thtml -Oincludes on a file containing a long .In argument.
41 Fixing this will probably require reworking the whole bufcat() concept.
42 loc ** exist * algo * size ** imp **
44 ************************************************************************
46 ************************************************************************
48 --- missing roff features ----------------------------------------------
50 - .ad (adjust margins)
51 .ad l -- adjust left margin only (flush left)
52 .ad r -- adjust right margin only (flush right)
53 .ad c -- center text on line
54 .ad b -- adjust both margins (alias: .ad n)
55 .na -- temporarily disable adjustment without changing the mode
56 .ad -- re-enable adjustment without changing the mode
57 Adjustment mode is ignored while in no-fill mode (.nf).
58 loc *** exist *** algo ** size ** imp ** (parser reorg would help)
61 found by naddy@ in xloadimage(1)
62 loc ** exist *** algo * size * imp *
64 - .nr third argument (auto-increment step size, requires \n+)
65 found by bentley@ in sbcl(1) Mon, 9 Dec 2013 18:36:57 -0700
66 loc * exist * algo * size * imp **
68 - .ns (no-space mode) occurs in xine-config(1)
69 reported by brad@ Sat, 15 Jan 2011 15:45:23 -0500
70 loc *** exist *** algo *** size ** imp *
72 - .ta (tab settings) occurs in ircbug(1) and probably gnats(1)
73 reported by brad@ Sat, 15 Jan 2011 15:50:51 -0500
74 also Tcl_NewStringObj(3) via wiz@ Wed, 5 Mar 2014 22:27:43 +0100
75 loc ** exist *** algo ** size ** imp **
77 - .ti (temporary indent)
78 found by naddy@ in xloadimage(1)
79 found by bentley@ in nmh(1) Mon, 23 Apr 2012 13:38:28 -0600
80 loc ** exist ** algo ** size * imp ** (parser reorg helps a lot)
83 found by jca@ in ratpoison(1) Sun, 30 Jun 2013 12:01:09 +0200
84 loc * exist ** algo ** size ** imp **
86 - \c (interrupted text) should prevent the line break
87 even inside .Bd literal; that occurs in chat(8)
88 also found in cclive(1) - DocBook output
89 loc ** exist *** algo ** size * imp *
92 found in cclive(1) DocBook output
93 Anthony J. Bentley on discuss@ Sat, 21 Sep 2013 22:29:34 -0600
94 loc ** exist ** algo ** size * imp ** (parser reorg helps a lot)
96 - \n+ and \n- numerical register increment and decrement
97 found by bentley@ in sbcl(1) Mon, 9 Dec 2013 18:36:57 -0700
98 loc * exist * algo * size * imp **
100 - \w'' improve width measurements
101 would not be very useful without an expression parser, see below
102 needed for Tcl_NewStringObj(3) via wiz@ Wed, 5 Mar 2014 22:27:43 +0100
103 loc ** exist *** algo *** size * imp ***
105 - using undefined strings or macros defines them to be empty
106 wl@ Mon, 14 Nov 2011 14:37:01 +0000
107 loc * exist * algo * size * imp *
109 --- missing mdoc features ----------------------------------------------
111 - fix bad block nesting involving multiple identical explicit blocks
112 see the OpenBSD mdoc_macro.c 1.47 commit message
113 loc * exist *** algo *** size * imp **
115 - .Bl -column .Xo support is missing
117 restore .Xr and .Dv to
118 lib/libc/compat-43/sigvec.3
119 lib/libc/gen/signal.3
120 lib/libc/sys/sigaction.2
121 loc * exist *** algo *** size * imp **
123 - edge case: decide how to deal with blk_full bad nesting, e.g.
124 .Sh .Nm .Bk .Nm .Ek .Sh found by jmc@ in ssh-keygen(1)
125 from jmc@ Wed, 14 Jul 2010 18:10:32 +0100
126 loc * exist *** algo *** size ** imp **
128 - \\ is now implemented correctly
129 * when defining strings and macros using .ds and .de
130 * when parsing roff(7) and man(7) macro arguments
131 It does not yet work in mdoc(7) macro arguments
132 because libmdoc does not yet use mandoc_getarg().
133 Also check what happens in plain text, it must be identical to \e.
135 - .Bd -centered implies -filled, not -unfilled, which is not
136 easy to implement; it requires code similar to .ce, which
137 we don't have either.
138 Besides, groff has bug causing text right *before* .Bd -centered
139 to be centered as well.
140 loc *** exist *** algo ** size ** imp ** (parser reorg would help)
142 - .Bd -filled should not be the same as .Bd -ragged, but align both
143 the left and right margin. In groff, it is implemented in terms
144 of .ad b, which we don't have either. Found in cksum(1).
145 loc *** exist *** algo ** size ** imp ** (parser reorg would help)
147 - implement blank `Bl -column', such as
151 loc * exist *** algo *** size * imp *
153 - explicitly disallow nested `Bl -column', which would clobber internal
154 flags defined for struct mdoc_macro
155 loc * exist * algo * size * imp **
157 - In .Bl -column .It, the end of the line probably has to be regarded
158 as an implicit .Ta, if there could be one, see the following mildly
159 ugly code from login.conf(5):
160 .Bl -column minpasswordlen program xetcxmotd
161 .It path Ta path Ta value of Dv _PATH_DEFPATH
164 reported by Michal Mazurek <akfaew at jasminek dot net>
165 via jmc@ Thu, 7 Apr 2011 16:00:53 +0059
166 loc * exist *** algo ** size * imp **
168 - inside `.Bl -column' phrases, punctuation is handled like normal
169 text, e.g. `.Bl -column .It Fl x . Ta ...' should give "-x -."
171 - inside `.Bl -column' phrases, TERMP_IGNDELIM handling by `Pf'
172 is not safe, e.g. `.Bl -column .It Pf a b .' gives "ab."
173 but should give "ab ."
175 - set a meaningful default if no `Bl' list type is assigned
176 loc * exist * algo * size * imp ** (already done?)
178 - have a blank `It' head for `Bl -tag' not puke
179 loc * exist * algo * size * imp ** (already done?)
181 - check whether it is correct that `D1' uses INDENT+1;
182 does it need its own constant?
183 loc * exist ** algo ** size * imp **
185 - prohibit `Nm' from having non-text HEAD children
186 (e.g., NetBSD mDNSShared/dns-sd.1)
187 (mdoc_html.c and mdoc_term.c `Nm' handlers can be slightly simplified)
189 - support translated section names
190 e.g. x11/scrotwm scrotwm_es.1:21:2: error: NAME section must be first
191 that one uses NOMBRE because it is spanish...
192 deraadt tends to think that section-dependent macro behaviour
193 is a bad idea in the first place, so this may be irrelevant
194 loc ** exist ** algo ** size * imp **
196 - When there is free text in the SYNOPSIS and that free text contains
197 the .Nm macro, groff somehow understands to treat the .Nm as an in-line
198 macro, while mandoc treats it as a block macro and breaks the line.
199 No idea how the logic for distinguishing in-line and block instances
200 should be, needs investigation.
201 uqs@ Thu, 2 Jun 2011 11:03:51 +0200
202 uqs@ Thu, 2 Jun 2011 11:33:35 +0200
203 loc * exist ** algo *** size * imp **
205 --- missing man features -----------------------------------------------
207 - -T[x]html doesn't stipulate non-collapsing spaces in literal mode
209 --- missing tbl features -----------------------------------------------
211 - look at the POSIX manuals in the books/man-pages-posix port,
212 they use some unsupported tbl(7) features.
213 loc * exist ** algo ** size ** imp ***
215 - use Unicode U+2500 to U+256C for table borders
216 in tbl(7) -Tutf-8 output
217 suggested by bentley@ Tue, 14 Oct 2014 04:10:55 -0600
218 loc * exist ** algo * size * imp **
220 - allow standalone `.' to be interpreted as an end-of-layout
221 delimiter instead of being thrown away as a no-op roff line
222 reported by Yuri Pankov, Wed 18 May 2011 11:34:59 CEST
223 loc ** exist ** algo ** size * imp **
225 --- missing eqn features -----------------------------------------------
227 - The "size" keyword is parsed, but ignored by the formatter.
228 loc * exist * algo * size * imp *
230 - The spacing characters `~', `^', and tab are currently ignored,
231 see User's Guide (Second Edition) page 2 section 4.
232 loc * exist * algo ** size * imp **
234 - Mark and lineup are parsed and ignored,
235 see User's Guide (Second Edition) page 5 section 15.
236 loc ** exist ** algo ** size ** imp **
238 --- missing misc features ----------------------------------------------
240 - italic correction (\/) in PostScript mode
241 Werner LEMBERG on groff at gnu dot org Sun, 10 Nov 2013 12:47:46
242 loc ** exist ** algo * size * imp *
244 - When makewhatis(8) encounters a FATAL parse error,
245 it silently treats the file as formatted, which makes no sense
246 at all for paths like man1/foo.1 - and which also contradicts
247 what the manual says at the end of the description.
248 The end result will be ENOENT for file names returned
249 by mansearch() in manpage.file.
250 loc * exist * algo * size * imp **
252 - makewhatis(8) for preformatted pages:
253 parse the section number from the header line
254 and compare to the section number from the directory name
255 loc * exist * algo * size * imp **
257 - Does makewhatis(8) detect missing NAME sections, missing names,
258 and missing descriptions in all the file formats?
259 loc * exist * algo * size * imp ***
261 - clean up escape sequence handling, creating three classes:
262 (1) fully implemented, or parsed and ignored without loss of content
263 (2) unimplemented, potentially causing loss of content
264 or serious mangling of formatting (e.g. \n) -> ERROR
265 see textproc/mgdiff(1) for nice examples
266 (3) undefined, just output the character -> perhaps WARNING
267 loc *** exist ** algo ** size ** imp *** (parser reorg helps)
269 - kettenis wants base roff, ms, and me Fri, 1 Jan 2010 22:13:15 +0100 (CET)
270 loc ** exist ** algo ** size *** imp *
272 --- compatibility checks -----------------------------------------------
274 - is .Bk implemented correctly in modern groff?
275 sobrado@ Tue, 19 Apr 2011 22:12:55 +0200
277 - compare output to Heirloom roff, Solaris roff, and
278 http://repo.or.cz/w/neatroff.git http://litcave.rudi.ir/
280 - look at AT&T DWB http://www2.research.att.com/sw/download
281 Carsten Kunze <carsten dot kunze at arcor dot de> has patches
282 Mon, 4 Aug 2014 17:01:28 +0200
284 - look at pages generated from reStructeredText, e.g. devel/mercurial hg(1)
285 These are a weird mixture of man(7) and custom autogenerated low-level
286 roff stuff. Figure out to what extent we can cope.
287 For details, see http://docutils.sourceforge.net/rst.html
288 noted by stsp@ Sat, 24 Apr 2010 09:17:55 +0200
289 reminded by nicm@ Mon, 3 May 2010 09:52:41 +0100
291 - look at pages generated from ronn(1) github.com/rtomayko/ronn
294 - look at pages generated from Texinfo source by yat2m, e.g. security/gnupg
295 First impression is not that bad.
297 - look at pages generated by pandoc; see
298 https://github.com/jgm/pandoc/blob/master/src/Text/Pandoc/Writers/Man.hs
299 porting planned by kili@ Thu, 19 Jun 2014 19:46:28 +0200
301 - check compatibility with Plan9:
302 http://swtch.com/usr/local/plan9/tmac/tmac.an
303 http://swtch.com/plan9port/man/man7/man.html
304 "Anthony J. Bentley" <anthonyjbentley@gmail.com> 28 Dec 2010 21:58:40 -0700
306 - check compatibility with the man(7) formatter
307 https://raw.githubusercontent.com/rofl0r/hardcore-utils/master/man.c
309 - check compatibility with
310 http://ikiwiki.info/plugins/contrib/mandoc/
311 https://github.com/schmonz/ikiwiki/compare/mandoc
312 Amitai Schlair Mon, 19 May 2014 14:05:53 -0400
314 ************************************************************************
315 * formatting issues: ugly output
316 ************************************************************************
318 - a column list with blank `Ta' cells triggers a spurrious
319 start-with-whitespace printing of a newline
322 .It Em Authentication<tab>Key Length
323 ought to render "Key Length" with emphasis, too,
324 see OpenBSD iked.conf(5).
325 reported again Nicolas Joly via wiz@ Wed, 12 Oct 2011 00:20:00 +0200
326 loc * exist *** algo *** size ** imp ***
328 - empty phrases in .Bl column produce too few blanks
329 try e.g. .Bl -column It Ta Ta
330 reported by millert Fri, 02 Apr 2010 16:13:46 -0400
331 loc * exist *** algo *** size * imp **
333 - .%T can have trailing punctuation. Currently, it puts the trailing
334 punctuation into a trailing MDOC_TEXT element inside its own scope.
335 That element should rather be outside its scope, such that the
336 punctuation does not get underlines. This is not trivial to
337 implement because .%T then needs some features of in_line_eoln() -
338 slurp all arguments into one single text element - and one feature
339 of in_line() - put trailing punctuation out of scope.
340 Found in mount_nfs(8) and exports(5), search for "Appendix".
341 loc ** exist ** algo *** size * imp **
343 - Trailing punctuation after .%T triggers EOS spacing, at least
344 outside .Rs (eek!). Simply setting ARGSFL_DELIM for .%T is not
345 the right solution, it sends mandoc into an endless loop.
346 reported by Nicolas Joly Sat, 17 Nov 2012 11:49:54 +0100
347 loc * exist ** algo ** size * imp **
349 - global variables in the SYNOPSIS of section 3 pages
350 .Vt vs .Vt/.Va vs .Ft/.Va vs .Ft/.Fa ...
351 from kristaps@ Tue, 08 Jun 2010 11:13:32 +0200
353 - in enclosures, mandoc sometimes fancies a bogus end of sentence
354 reminded by jmc@ Thu, 23 Sep 2010 18:13:39 +0059
355 loc * exist ** algo *** size * imp ***
357 - formatting /usr/local/man/man1/latex2man.1 with groff and mandoc
358 reveals lots of bugs both in groff and mandoc...
359 reported by bentley@ Wed, 22 May 2013 23:49:30 -0600
361 --- PDF issues ---------------------------------------------------------
363 - PDF output doesn't use a monospaced font for .Bd -literal
364 Example: "mandoc -Tpdf afterboot.8 > output.pdf && pdfviewer output.pdf".
365 Search the text "Routing tables".
366 Also check what PostScript mode does when fixing this.
367 reported by juanfra@ Wed, 04 Jun 2014 21:44:58 +0200
368 instructions from juanfra@ Wed, 11 Jun 2014 02:21:01 +0200
369 add a new <</Type /Font>> block to the PDF files with /BaseFont /Courier
370 and change the /Name from /F0 to the new font (/F5 (?)).
371 loc * exist ** algo ** size * imp **
373 --- HTML issues --------------------------------------------------------
375 - <dl><dt><dd> formatting is ugly
376 hints are easy to find on the web, e.g.
377 http://stackoverflow.com/questions/1713048/
378 see also matthew@ Fri, 18 Jul 2014 19:25:12 -0700
379 loc * exist * algo ** size * imp ***
381 - jsg on icb, Nov 3, 2014:
382 try to guess Xr in man(7) for hyperlinking
384 - The tables used to render the three-part page headers actually force
385 the width of the <body> to the max-width given for <html>.
386 Not yet sure how to fix that...
387 Observed by an Anonymous Coward on undeadly.org:
388 http://undeadly.org/cgi?action=article&sid=20140925064244&pid=1
389 loc * exist * algo ** size * imp ***
391 - consider whether <var> can be used for Ar Dv Er Ev Fa Va.
392 from bentley@ Wed, 13 Aug 2014 09:17:55 -0600
394 - check https://github.com/trentm/mdocml
396 ************************************************************************
397 * formatting issues: gratuitous differences
398 ************************************************************************
400 - .Fn reopens a new scope after punctuation in mandoc,
401 but closes its scope for good in groff.
402 Do we want to change mandoc or groff?
403 Steffen Nurpmeso Sat, 08 Nov 2014 13:34:59 +0100
404 loc * exist ** algo ** size * imp **
406 - .Rv (and probably .Ex) print different text if an `Nm' has been named
407 or not (run a manual without `Nm blah' to see this). I'm not sure
408 that this exists in the wild, but it's still an error.
409 loc * exist * algo * size * imp * (already done?)
411 - In .Bl -bullet, the groff bullet is "+\b+\bo\bo", the mandoc bullet
412 is just "o\bo". The problem is to not break ps/pdf when fixing.
413 see for example OpenBSD ksh(1)
414 loc ** exist ** algo ** size * imp **
416 - In .Bl -enum -width 0n, groff continues one the same line after
417 the number, mandoc breaks the line.
418 mail to kristaps@ Mon, 20 Jul 2009 02:21:39 +0200
419 loc * exist ** algo ** size * imp **
421 - .Pp between two .It in .Bl -column should produce one,
422 not two blank lines, see e.g. login.conf(5).
423 reported by jmc@ Sun, 17 Apr 2011 14:04:58 +0059
424 reported again by sthen@ Wed, 18 Jan 2012 02:09:39 +0000 (UTC)
425 loc * exist *** algo ** size * imp **
427 - If the *first* line after .It is .Pp, break the line right after
428 the tag, do not pad with space characters before breaking.
429 See the description of the a, c, and i commands in sed(1).
430 loc * exist ** algo ** size * imp **
432 - If the first line after .It is .D1, do not assert a blank line
433 in between, see for example tmux(1).
434 reported by nicm@ 13 Jan 2011 00:18:57 +0000
435 loc * exist ** algo ** size * imp **
437 - Trailing punctuation after .It should trigger EOS spacing.
438 reported by Nicolas Joly Sat, 17 Nov 2012 11:49:54 +0100
439 Probably, this should be fixed somewhere in termp_it_pre(), not sure.
440 loc * exist ** algo ** size * imp **
443 should be "NetBSD 1.0A", not "NetBSD 1.0a",
444 see OpenBSD ccdconfig(8).
445 loc * exist * algo * size * imp **
447 - In .Bl -tag, if a tag exceeds the right margin and must be continued
448 on the next line, it must be indented by -width, not width+1;
449 see "rule block|pass" in OpenBSD ifconfig(8).
450 loc * exist *** algo ** size * imp **
452 - When the -width string contains macros, the macros must be rendered
453 before measuring the width, for example
454 .Bl -tag -width ".Dv message"
455 in magic(5), located in src/usr.bin/file, is the same
456 as -width 7n, not -width 11n.
457 The same applies to .Bl -column column widths;
458 reported again by Nicolas Joly Thu, 1 Mar 2012 13:41:26 +0100 via wiz@ 5 Mar
459 reported again by Franco Fichtner Fri, 27 Sep 2013 21:02:28 +0200
460 loc *** exist *** algo *** size ** imp ***
461 An easy partial fix would be to just skip the first word if it starts
462 with a dot, including any following white space, when measuring.
463 loc * exist * algo * size * imp ***
465 - The \& zero-width character counts as output.
466 That is, when it is alone on a line between two .Pp,
467 we want three blank lines, not two as in mandoc.
468 loc ** exist ** algo ** size * imp **
470 - Header lines of excessive length:
471 Port OpenBSD man_term.c rev. 1.25 to mdoc_term.c
472 and document it in mdoc(7) and man(7) COMPATIBILITY
473 found while talking to Chris Bennett
474 loc * exist * algo * size * imp *
476 - trailing whitespace must be ignored even when followed by a font escape,
480 operate in batch mode
482 loc ** exist ** algo ** size * imp **
484 ************************************************************************
486 ************************************************************************
488 - check that MANDOCERR_BADTAB is thrown in the right cases,
489 i.e. when finding a literal tab character in fill mode,
490 and possibly change the wording of the warning message
491 to refer to fill mode, not literal mode
492 See the mail from Werner LEMBERG on the groff list,
493 Fri, 14 Feb 2014 18:54:42 +0100 (CET)
494 loc * exist ** algo ** size * imp **
496 - warn about attempts to call non-callable macros
497 Steffen Nurpmeso Tue, 11 Nov 2014 22:55:16 +0100
498 Note that formatting is inconsistent in groff.
499 .Fn Po prints "Po()", .Ar Sh prints "file ..." and no "Sh".
500 Relatively hard because the relevant code is scattered
501 all over mdoc_macro.c and all subtly different.
502 loc ** exist ** algo ** size ** imp **
504 - warn about "new sentence, new line"
505 loc ** exist ** algo *** size * imp **
507 - mandoc_special does not really check the escape sequence,
508 but just the overall format
509 loc ** exist ** algo *** size ** imp **
511 - integrate mdoclint into mandoc ("end-of-line whitespace" thread)
512 from jmc@ Mon, 13 Jul 2009 17:12:09 +0100
513 from kristaps@ Mon, 13 Jul 2009 18:34:53 +0200
514 from jmc@ Mon, 13 Jul 2009 17:45:37 +0059
515 from kristaps@ Mon, 13 Jul 2009 19:02:03 +0200
516 (mostly done, check what remains)
518 - -Tlint parser errors and warnings to stdout
519 to tech@mdocml, naddy@ Wed, 28 Sep 2011 11:21:46 +0200
520 wait! kristaps@ Sun, 02 Oct 2011 17:12:52 +0200
522 - for system errors, use errno/strerror/warn/err
524 ************************************************************************
525 * documentation issues
526 ************************************************************************
528 - mention hyphenation rules:
529 breaking at letter-letter in text mode (not macro args)
530 proper hyphenation is unimplemented
532 - talk about spacing around delimiters
533 to jmc@, kristaps@ Sat, 23 Apr 2011 17:41:27 +0200
535 - mark macros as: page structure domain, manual domain, general text domain
538 - mention /usr/share/misc/mdoc.template in mdoc(7)?
540 - Is all the content from http://www.std.com/obi/BSD/doc/usd/28.tbl/tbl
543 ************************************************************************
545 ************************************************************************
547 - Why are we using MAP_SHARED, not MAP_PRIVATE for mmap(2)?
548 How does SQLITE_CONFIG_PAGECACHE actually work? Document it!
549 from kristaps@ Sat, 09 Aug 2014 13:51:36 +0200
551 Several areas can be cleaned up to make mandoc even faster. These are
553 - improve hashing mechanism for macros (quite important: performance)
555 - improve hashing mechanism for characters (not as important)
557 - the PDF file is HUGE: this can be reduced by using relative offsets
559 - instead of re-initialising the roff predefined-strings set before each
560 parse, create a read-only version the first time and copy it
561 loc * exist ** algo ** size * imp **
563 ************************************************************************
565 ************************************************************************
567 - We use the input line number at several places to distinguish
568 same-line from different-line input. That plainly doesn't work
569 with user-defined macros, leading to random breakage.
571 - Find better ways to prevent endless loops
572 in roff(7) macro and string expansion.
574 - Finish cleanup of date handling.
575 Decide which formats should be recognized where.
576 Update both mdoc(7) and man(7) documentation.
577 Triggered by Tim van der Molen Tue, 22 Feb 2011 20:30:45 +0100
579 - struct mparse refactoring
580 Steffen Nurpmeso Thu, 04 Sep 2014 12:50:00 +0200
582 - Consider creating some views that will make the database more
583 readable from the sqlite3 shell. Consider using them to
584 abstract from the database structure, too.
585 suggested by espie@ Sat, 19 Apr 2014 14:52:57 +0200
587 ************************************************************************
589 ************************************************************************
591 - Enable HTTP compression by detecting gzip encoding and filtering
593 - Sandbox (see OpenSSH).
594 - Enable caching support via HTTP 304 and If-Modified-Since.
595 - Allow for cgi.h to be overridden by CGI environment variables.
596 Otherwise, binary distributions will inherit the compile-time
597 behaviour, which is not optimal.
598 - Have Mac OSX systems automatically disable -static compilation of the
599 CGI: -static isn't supported.