Update htmldoc to 1.8.27.
Based on PR 40223.

Pkgsrc changes:
* Change HOMPAGE for open source version.
* Add missng dependency on devel/zlib.
* Optionify of SSL support and let gnutls to selectable.
* Rename undocumented htmldoc-gui option to x11, it's better match for pkgname.

CHANGES IN HTMLDOC v1.8.27

    BUG FIXES

- Fixed a crash bug that appeared when more than 10 blank
  pages were present in a document (PR #6223)
- Color changes were not reflected in PRE text (STR #129)
- Remote URLs did not always work on older operating
  systems (PR #6179)
- Image filenames using % escapes were not decoded
  properly.
- Rows using BGCOLOR that spanned across multiple pages
  did not render properly (PR #6149)
- Rows no longer start on a new page due to a cell with
  both HEIGHT and ROWSPAN specified (PR #6086)
- CMYK JPEG images caused HTMLDOC to crash (PR #6106)
- Table cell width calculations didn't always account for
  the proper minimum width (STR #121)
- Images were not copied when generating indexed HTML
  output to a directory (STR #117)
- Changing the bottom margin resulted in text that was
  formatted below the bottom margin.
- The Monospace-Oblique font was not embedded properly in
  PDF files.

CHANGES IN HTMLDOC v1.8.26

    BUG FIXES

- Outline and keyword strings in PDF files are now stored
  as Unicode (STR #113)
- The Flate compression code could get in an infinite
  loop if it ran out of memory (STR #101)
- Book files saved from the GUI did not handle filenames
  with spaces (STR #105)
- Fixed and re-enabled the ASCII85Device filter support
  in PostScript Level 2/3 output (STR #116)
- Character entities in the first word of a file were not
  rendered properly (STR #111)
- Fixed-size table columns were incorrectly resized when
  a table width was also specified and there was extra
  space to distribute (PR #6062)
- Text could "walk" up or down when in-line images were
  used (PR #6034)
- Row backgrounds incorrectly replaced cell backgrounds
  when the first cell in a row used ROWSPAN (PR #6033, PR
  #6036)
- HTMLDOC did not correctly parse FONT FACE attributes
  (PR #6006)
- Images in Level 2/3 PostScript output did not work on
  some printers (PR #6000)
- The GUI did not use the first page header (PR #5978)

CHANGES IN HTMLDOC v1.8.25

    NEW FEATURES

- Added "--overflow" and "--no-overflow" command-line
  options to show or hide the content-too-large errors;
  the default is "--no-overflow".
- Added "--header1" command-line option and "HEADER1"
  page comments to set the page header for the first page
  of each chapter.
- Added "timing" and "remotebytes" debug data generation.
- Added DejaVu font collection to better support Cyrillic
  and Greek text; the new fonts are available under the
  generic names "monospace", "sans", and "serif".
- Added "--referer" command-line option and corresponding
  CGI-mode support to pass Referer: information in HTTP
  requests (STR #91)

    CHANGES:

- On Windows, HTMLDOC now logs CGI mode errors to a file
  called "htmldoc.log" in the Windows temporary
  directory.
- HTMLDOC no longer uses Base-85 encoding for image data
  when producing Level 2 and 3 PostScript output. It
  appears that many printers and PostScript interpreters
  cannot properly decode this data when the original
  image data is not a multiple of 8 bits.
- HTMLDOC now renders STRONG elements in boldface instead
  of bold-italic to match the W3C recommendations.
- HTMLDOC now automatically inserts a TR element before a
  TD or TH element as needed to improve web site
  compatibility; this also triggers a HTML error in
  --strict mode.

    BUG FIXES

- "$HFIMAGEn" didn't work in a header/footer string.
- HTMLDOC could crash when rendering a table.
- Book files were not used in CGI mode (STR #69)
- Cookies were not sent in HTTP requests (STR #71)
- Table cells were not aligned properly when the ROWSPAN
  attribute was set to 1 (STR #73)
- HTMLDOC crashed when rendering unresolved hyperlinks in
  aligned images (STR #62)
- Documented the HTMLDOC_NOCGI environment variable (STR
  #63)
- HTMLDOC sometimes crashed when rendering tables with
  background colors (STR #65)
- HTMLDOC would crash when writing encrypted strings
  longer than 1024 bytes (STR #66)
- HTMLDOC didn't set the data directory when running in
  CGI mode on Windows.
- HTMLDOC could crash when loading the Symbol.afm file
  (STR #93)
- HTMLDOC did not always honor HEIGHT attributes in table
  rows.
- Tables with a mix of colspan and rowspan sometimes
  caused cells to be moved vertically outside the cell.

CHANGES IN HTMLDOC v1.8.24

    NEW FEATURES

- HTMLDOC now provides limited cookie support via the
  "--cookies" command-line option and via the cookies
  passed by a browser in CGI mode.
- HTMLDOC now features a CGI mode which provides PDF
  conversion functionality for web servers.
- HTMLDOC now generates a document outline for each
  input file or URL in webpage mode; the outline shows
  the title for the file and links to the first page
  containing that file.
- HTMLDOC now offers an "htmlsep" output type which
  generates HTML output with a separate file for each
  heading in the table of contents.
- HTMLDOC now includes LINK elements in generated HTML
  so that intelligent browsers like Mozilla can show
  next/prev/contents/top buttons.
- HTMLDOC now supports the BORDERCOLOR attribute for
  tables, a MSIE extension.
- The "strict HTML" mode now reports unresolved local
  links.
- Added support for HP LaserJet 5000 and Xerox DocuPrint
  2000/100 printer commands.
- Added multiple header/footer image support.
- Links to external URLs are now resolved so that the
  output file can be moved without affecting them.

    CHANGES

- The command-line now allows --fontsize values from 4
  to 26 to match the GUI.
- Now use a 0.001 point tolerance when checking for
  content that overflows the page/cell.
- HTMLDOC no longer enables interpolation of 2-color
  images.
- The default vertical alignment of images is "BOTTOM"
  to match the HTML specification.
- Paragraph spacing is only applied to the first table
  after a paragraph.
- The tabloid media size was 10 points too short in
  length.
- The table formatter now subtracts the outside border
  and padding widths for percentage-based widths.  This
  helps to eliminate "truncation or overlapping" errors.
- Dropped support for FLTK 1.0.x when building the GUI.
- The default vertical alignment is now "bottom" inside
  paragraphs to correctly align different sized text and
  images to the baseline.
- Indexed images are now written as PDF image objects
  when encryption is enabled; this works around a
  serious bug in Acrobat 6 which tries to decrypt the
  colormap of in-line images twice, causing some very
  strange colors!
- Table captions can now be bottom aligned.
- Blocks now break at the bottom of a page if the
  current line height + standard line height goes below
  the bottom of the page; this prevents images with
  captions from getting erroneously moved to the top of
  the next page.
- Character entities are now supported in HTML
  attributes and unknown or invalid character entities
  are left as plain text.
- Changed handling of NOWRAP for some tables.
- The --permissions option now supports multiple
  permission keywords in a single invocation.
- Dropped support for MacOS 9 and earlier.
- HTMLDOC now breaks between images that are too large
  to fit on a single line, to match the behavior of
  Mozilla/Netscape (STR #7).
- HTMLDOC now handles XHTML input more cleanly.
- HTMLDOC no longer specifies an interpolation
  preference for images in PostScript or PDF output (STR
  #8)
- The DT element no longer applies an italic style (PR
  #5178)
- HTMLDOC now ignores content inside a STYLE element
  (PR #5183)

    BUG FIXES

- Switching between landscape and portrait orientations
  would cause margin creepage.
- Images did not default to align=bottom, and the
  align=bottom line spacing calculation was incorrect.
- Whitespace before a link was underlined.
- Fixed a table column sizing bug.
- HTMLDOC didn't read back the HTTP response properly in
  all situations.
- Fixed some more PNG transparency cases.
- The PageBoundingBox comments in PostScript output did
  not account for the back page when duplexing was
  enabled.
- HTMLDOC generated an incorrect image mask for some
  images.
- The first page of each chapter did not use the custom
  page number if it was placed inside the heading.
- HTMLDOC did not reset the rendering cache before each
  page when producing N-up output; this caused font
  errors in some cases that prevented the document from
  printing or displaying properly.
- Eliminated a common cause of "table too wide"
  formatting errors,
- Fixed a bug when applying a table background color to
  a cell without a border that cross a page boundary.
- Fixed some calls to strcpy with overlapping arguments.
- The names object was never set when the name objects
  were written.
- Character entities were not decoded/encoded inside
  HTML comments.
- The current heading was not always correctly
  substituted when used in the page header or footer.
- When converting web pages from the GUI, the
  table-of-contents page number preferences were
  incorrectly used.
- PDF page effects/transitions were not put in the right
  part of the page dictionary, causing them not to be
  used by the PDF reader application.
- The _HD_OMIT_TOC attribute was not being honored for
  HTML output.
- HTMLDOC now handles "open" messages from the MacOS X
  Finder (STR #3)
- The GUI did not load or save the "strict HTML" setting
  (STR #6)
- The HTML version of the title page did not set the ALT
  attribute for the title image (STR #10)
- The HTML version of the table of contents did not
  correctly nest the lists in the parent items (STR #10)
- Borders around left and right-aligned images were not
  drawn properly (PR #5112)
- Grayscale PDF output was not truly grayscale (STR #32)
- Fixed a table-of-contents bug introduced in 1.8.24rc1
  which caused the PDF document outline and actual TOC
  pages were not rendered properly (STR #37)
- Links were not rendered due to a bug that was
  introduced in 1.8.24rc2 (STR #41)

(obache)