Add support for the Haiku operating system and its window system

* .gitignore: Add binaries specific to Haiku.

* Makefie.in (HAVE_BE_APP): New variable.
(install-arch-dep): Install Emacs and Emacs.pdmp when
using Haiku.

* configure.ac: Detect and configure for Haiku and
various related configurations.
(be-app, be-freetype, be-cairo): New options.
(HAVE_BE_APP, HAIKU_OBJ, HAIKU_CXX_OBJ)
(HAIKU_LIBS, HAIKU_CFLAGS): New variables.
(HAIKU, HAVE_TINY_SPEED_T): New define.
(emacs_config_features): Add BE_APP.

* doc/emacs/Makefile.in (EMACSSOURCES): Add Haiku
appendix.

* doc/emacs/emacs.texi: Add Haiku appendix to menus and
include it.

* doc/emacs/haiku.texi: New Haiku appendix.

* doc/lispref/display.texi (Defining Faces, Window Systems):
Explain meaning of `haiku' as a window system identifier.
(haiku-use-system-tooltips): Explain meaning of system
tooltips on
Haiku.

* doc/lispref/frames.texi (Multiple Terminals): Explain
meaning of haiku as a display type.
(Frame Layout): Clarify section for Haiku frames.
(Size Parameters): Explain limitations of fullwidth and
fullheight on Haiku.
(Management Parameters): Explain limitations of
inhibiting double buffering on builds with Cairo,
and the inability of frames with no-accept-focus to
receive keyboard input on Haiku.
(Font and Color Parameters): Explain the different font
backends available on Haiku.
(Raising and Lowering): Explain that lowering and
restacking frames doesn't work on Haiku.
(Child Frames): Explain oddities of child frame
visibility on Haiku.

* doc/lispref/os.texi (System Environment): Explain
meaning of haiku.
* etc/MACHINES: Add appropriate notices for Haiku.
* etc/NEWS: Document changes.
* etc/PROBLEMS: Document font spacing bug on Haiku.

* lib-src/Makefile.in: Build be-resources binary on
Haiku.
(CXX, CXXFLAGS, NON_CXX_FLAGS, ALL_CXXFLAGS)
(HAVE_BE_APP, HAIKU_LIBS, HAIKU_CFLAGS): New variables.
(DONT_INSTALL): Add be-resources binary if on Haiku.
(be-resources): New target.

* lib-src/be_resources: Add helper binary for setting
resources on the Emacs application.

* lib-src/emacsclient.c (decode_options): Set
alt_display to "be" on Haiku.

* lisp/cus-edit.el (custom-button, custom-button-mouse)
(custom-button-unraised, custom-button-pressed): Update
face definitions for Haiku.

* lisp/cus-start.el: Add haiku-debug-on-fatal-error and
haiku-use-system-tooltips.

* lisp/faces.el (face-valid-attribute-values): Clarify
attribute comment for Haiku.
(tool-bar): Add appropriate toolbar color for Haiku.

* lisp/frame.el (haiku-frame-geometry)
(haiku-mouse-absolute-pixel-position)
(haiku-set-mouse-absolute-pixel-position)
(haiku-frame-edges)
(haiku-frame-list-z-order): New function declarations.

(frame-geometry, frame-edges)
(mouse-absolute-pixel-position)
(set-mouse-absolute-pixel-position)
(frame-list-z-order): Call appropriate window system
functions on Haiku.

(display-mouse-p, display-graphic-p)
(display-images-p, display-pixel-height)
(display-pixel-width, display-mm-height)
(display-mm-width, display-backing-store)
(display-save-under, display-planes)
(display-color-cells, display-visual-class): Update type
tests for Haiku.

* lisp/international/mule-cmds.el
(set-coding-system-map): Also
prevent set-terminal-coding-system from appearing in the menu
bar on Haiku.

* lisp/loadup.el: Load Haiku-specific files when built
with Haiku, and don't rename newly built Emacs on Haiku as BFS
doesn't support hard links.

* lisp/menu-bar.el (menu-bar-open): Add for Haiku.

* lisp/mwheel.el (mouse-wheel-down-event): Expect
wheel-up on Haiku.
(mouse-wheel-up-event): Expect wheel-down on Haiku.
(mouse-wheel-left-event): Expect wheel-left on Haiku.
(mouse-wheel-right-event): Expect wheel-right on Haiku.

* lisp/net/browse-url.el
(browse-url--browser-defcustom-type):
Add option for WebPositive.
(browse-url-webpositive-program): New variable.
(browse-url-default-program): Search for WebPositive.
(browse-url-webpositive): New function.

* lisp/net/eww.el (eww-form-submit, eww-form-file)
(eww-form-checkbox, eww-form-select): Define faces
appropriately for Haiku.

* lisp/term/haiku-win.el: New file.

* lisp/tooltip.el (menu-or-popup-active-p): New function
declaration.
(tooltip-show-help): Don't use tooltips on Haiku when a
menu is active.

* lisp/version.el (haiku-get-version-string): New
function declaration.
(emacs-version): Add Haiku version string if
appropriate.

* src/Makefile.in: Also produce binary named "Emacs"
with Haiku resources set.

(CXX, HAIKU_OBJ, HAIKU_CXX_OBJ, HAIKU_LIBS)
(HAIKU_CFLAGS, HAVE_BE_APP, NON_CXX_FLAGS)
(ALL_CXX_FLAGS): New variables.

(.SUFFIXES): Add .cc.
(.cc.o): New target.
(base_obj): Add Haiku C objects.
(doc_obj, obj): Split objects that should scanned for
documentation into doc_obj.
(SOME_MACHINE_OBJECTS): Add appropriate Haiku C objects.
(all): Depend on Emacs and Emacs.pdmp on Haiku.
(LIBES): Add Haiku libraries.
(gl-stamp)
($(etc)/DOC): Scan doc_obj instead of obj
(temacs$(EXEEXT): Use C++ linker on Haiku.
(ctagsfiles3): New variable.
(TAGS): Scan C++ files.

* src/alloc.c (garbage_collect): Mark Haiku display.

* src/dispextern.h (HAVE_NATIVE_TRANSFORMS): Also enable
on Haiku.
(struct image): Add fields for Haiku transforms.
(RGB_PIXEL_COLOR): Define to unsigned long on Haiku as
well.
(sit_for): Also check USABLE_SIGPOLL.
(init_display_interactive): Set initial window system to
Haiku on Haiku builds.

* src/emacs.c (main): Define Haiku syms and init haiku
clipboard.
(shut_down_emacs): Quit BApplication on Haiku and
trigger debug
on aborts if haiku_debug_on_fatal_error.
(Vsystem_type): Update docstring.

* src/fileio.c (next-read-file-uses-dialog-p): Enable on
Haiku.

* src/filelock.c (WTMP_FILE): Only define if BOOT_TIME
is also defined.

* src/floatfns.c (double_integer_scale): Work around
Haiku libroot brain damage.

* src/font.c (syms_of_font): Define appropriate font
driver symbols for Haiku builds with various options.

* src/font.h: Also enable ftcrfont on Haiku builds with
Cairo.
(font_data_structures_may_be_ill_formed): Also enable on
Haiku builds that have Cairo.

* src/frame.c (Fframep): Update doc-string for Haiku
builds and return haiku if appropriate.
(syms_of_frame): New symbol `haiku'.

* src/frame.h (struct frame): Add output data for Haiku.
(FRAME_HAIKU_P): New macro.
(FRAME_WINDOW_P): Test for Haiku frames as well.

* src/ftcrfont.c (RED_FROM_ULONG, GREEN_FROM_ULONG)
(BLUE_FROM_ULONG): New macros.
(ftcrfont_draw): Add haiku specific code for Haiku
builds with Cairo.

* src/ftfont.c (ftfont_open): Set face.
(ftfont_has_char, ftfont_text_extents): Work around
crash.
(syms_of_ftfont): New symbol `mono'.

* src/ftfont.h (struct font_info): Enable Cairo-specific
fields for Cairo builds on Haiku.

* src/haiku_draw_support.cc:
* src/haiku_font_support.cc:
* src/haiku_io.c:
* src/haiku_select.cc:
* src/haiku_support.cc:
* src/haiku_support.h:
* src/haikufns.c:
* src/haikufont.c:
* src/haikugui.h:
* src/haikuimage.c:
* src/haikumenu.c:
* src/haikuselect.c:
* src/haikuselect.h:
* src/haikuterm.c:
* src/haikuterm.h: Add new files for Haiku windowing
support.

* src/haiku.c: Add new files for Haiku operating system
support.

* src/image.c: Implement image transforms and native XPM
support
on Haiku.

(GET_PIXEL, PUT_PIXEL, NO_PIXMAP)
(PIX_MASK_RETAIN, PIX_MASK_DRAW)
(RGB_TO_ULONG, RED_FROM_ULONG, GREEN_FROM_ULONG)
(BLUE_FROM_ULONG, RED16_FROM_ULONG, GREEN16_FROM_ULONG)
(BLUE16_FROM_ULONG): Define to appropriate values on
Haiku.

(image_create_bitmap_from_data): Add Haiku support.
(image_create_bitmap_from_file): Add TODO on Haiku.
(free_bitmap_record): Free bitmap on Haiku.
(image_size_in_bytes): Implement for Haiku bitmaps.
(image_set_transform): Implement on Haiku.
(image_create_x_image_and_pixmap_1): Implement on Haiku,
24-bit or 1-bit only.
(image_destroy_x_image, image_get_x_image): Use correct
img and pixmap values on Haiku.
(lookup_rgb_color): Use correct macro on Haiku.
(image_to_emacs_colors): Implement on Haiku.
(image_disable_image): Disable on Haiku.
(image_can_use_native_api): Test for translator presence
on Haiku.
(native_image_load): Use translator on Haiku.
(imagemagick_load_image): Add Haiku-specific quirks.
(Fimage_transforms_p): Allow rotate90 on Haiku.
(image_types): Enable native XPM support on Haiku.
(syms_of_image): Enable XPM images on Haiku.

* src/keyboard.c (kbd_buffer_get_event)
(handle_async_input, handle_input_available_signal)
(handle_user_signal, Fset_input_interrupt_mode)
(init_keyboard): Check for USABLE_SIGPOLL along with
USABLE_SIGIO.

* src/lisp.h (pD): Work around broken Haiku headers.
(HAVE_EXT_MENU_BAR): Define on Haiku.
(handle_input_available_signal): Enable if we just have
SIGPOLL as well.

* src/menu.c (have_boxes): Return true on Haiku.
(single_menu_item): Enable toolkit menus on Haiku.
(find_and_call_menu_selection): Also enable on Haiku.

* src/process.c (keyboard_bit_set): Enable with only
usable SIGPOLL.
(wait_reading_process_output): Test for SIGPOLL as well
as SIGIO availability.

* src/sound.c (sound_perror, vox_open)
(vox_configure, vox_close): Enable for usable SIGPOLL as
well.

* src/sysdep.c (sys_subshell): Enable for usable SIGPOLL.
(reset_sigio): Make conditional on F_SETOWN.
(request_sigio, unrequest_sigio)
(emacs_sigaction_init): Also handle SIGPOLLs.
(init_sys_modes): Disable TCXONC usage on Haiku, as it
doesn't have any ttys other than pseudo ttys, which don't
support C-s/C-q flow control, and causes compiler warnings.
(speeds): Disable high speeds if HAVE_TINY_SPEED_T.

* src/termhooks.h (enum output_method): Add output_haiku.
(struct terminal): Add Haiku display info.
(TERMINAL_FONT_CACHE): Enable for Haiku.

* src/terminal.c (Fterminal_live_p): Return `haiku' if
appropriate.
* src/verbose.mk.in (AM_V_CXX, AM_V_CXXLD): New logging
variables.

* src/xdisp.c (redisplay_internal)
(note_mouse_highlight): Return on Haiku if a popup is activated.
(display_menu_bar): Return on Haiku if frame is a Haiku
frame.

* src/xfaces.c (GCGraphicsExposures): Enable correctly on Haiku.
(x_create_gc): Enable dummy GC code on Haiku.

* src/xfns.c (x-server-version, x-file-dialog): Add
Haiku specifics to doc strings.

* src/xterm.c (syms_of_xterm): Add Haiku information to
doc string.

3 files changed, 144 insertions, 0 deletions

diff --git a/doc/emacs/Makefile.in b/doc/emacs/Makefile.in
index 69d39efa8b9..dde3ae83c16 100644
--- a/doc/emacs/Makefile.in
+++ b/doc/emacs/Makefile.in
@@ -140,6 +140,7 @@ EMACSSOURCES= \
 	${srcdir}/xresources.texi \
 	${srcdir}/anti.texi \
 	${srcdir}/macos.texi \
+	$(srcdir)/haiku.texi \
 	${srcdir}/msdos.texi \
 	${srcdir}/gnu.texi \
 	${srcdir}/glossary.texi \
diff --git a/doc/emacs/emacs.texi b/doc/emacs/emacs.texi
index 83847fb8f12..ce92435ae70 100644
--- a/doc/emacs/emacs.texi
+++ b/doc/emacs/emacs.texi
@@ -221,6 +221,7 @@ Appendices
 * X Resources::         X resources for customizing Emacs.
 * Antinews::            Information about Emacs version 27.
 * Mac OS / GNUstep::     Using Emacs under macOS and GNUstep.
+* Haiku::               Using Emacs on Haiku.
 * Microsoft Windows::   Using Emacs on Microsoft Windows and MS-DOS.
 * Manifesto::           What's GNU?  Gnu's Not Unix!
 
@@ -1249,6 +1250,11 @@ Emacs and macOS / GNUstep
 * Mac / GNUstep Events::        How window system events are handled.
 * GNUstep Support::             Details on status of GNUstep support.
 
+Emacs and Haiku
+
+* Haiku Basics::        Basic Emacs usage and installation under Haiku.
+* Haiku Fonts::         The various options for displaying fonts on Haiku.
+
 Emacs and Microsoft Windows/MS-DOS
 
 * Windows Startup::     How to start Emacs on Windows.
@@ -1618,6 +1624,7 @@ Lisp programming.
 
 @include anti.texi
 @include macos.texi
+@include haiku.texi
 @c Includes msdos-xtra.
 @include msdos.texi
 @include gnu.texi
diff --git a/doc/emacs/haiku.texi b/doc/emacs/haiku.texi
new file mode 100644
index 00000000000..a2dc6e14d0e
--- /dev/null
+++ b/doc/emacs/haiku.texi
@@ -0,0 +1,136 @@
+@c This is part of the Emacs manual.
+@c Copyright (C) 2021 Free Software Foundation, Inc.
+@c See file emacs.texi for copying conditions.
+@node Haiku
+@appendix Emacs and Haiku
+@cindex Haiku
+
+  Haiku is a Unix-like operating system that originated as a
+re-implementation of the operating system BeOS.
+
+  This section describes the peculiarities of using Emacs built with
+the Application Kit, the windowing system native to Haiku.  The
+oddities described here do not apply to using Emacs on Haiku built
+without windowing support, or built with X11.
+
+@menu
+* Haiku Basics::        Basic Emacs usage and installation under Haiku.
+* Haiku Fonts::         The various options for displaying fonts on Haiku.
+@end menu
+
+@node Haiku Basics
+@section Installation and usage peculiarities under Haiku
+@cindex haiku application
+@cindex haiku installation
+
+  Emacs installs two separate executables under Haiku; it is up to the
+user to decide which one suits him best: A regular executable, with
+the lowercase name @code{emacs}, and a binary containing
+Haiku-specific application metadata, with the name @code{Emacs}.
+
+@cindex launching Emacs from the tracker
+@cindex tty Emacs in haiku
+  If you are launching Emacs from the Tracker, or want to make the
+Tracker open files using Emacs, you should use the binary named
+@code{Emacs}; ff you are going to use Emacs in the terminal, or wish
+to launch separate instances of Emacs, or do not care for the
+aforementioned system integration features, use the binary named
+@code{emacs} instead.
+
+@cindex modifier keys and system keymap (Haiku)
+@cindex haiku keymap
+  On Haiku, unusual modifier keys such as the Hyper key are
+unsupported.  By default, the super key corresponds with the option
+key defined by the operating system, the meta key with the command
+key, the control key with the system control key, and the shift key
+with the system shift key.  On a standard PC keyboard, Haiku should
+map these keys to positions familiar to those using a GNU system, but
+this may require some adjustment to your system's configuration to
+work.
+
+  It is impossible to type accented characters using the system super
+key map.
+
+  You can customize the correspondence between modifier keys known to
+the system, and those known to Emacs.  The variables that allow for
+that are described below.
+
+@cindex modifier key customization (Haiku)
+You can customize which Emacs modifiers the various system modifier
+keys correspond to through the following variables:
+
+@table @code
+@vindex haiku-meta-keysym
+@item haiku-meta-keysym
+The system modifier key that will be treated as the Meta key by Emacs.
+It defaults to @code{command}.
+
+@vindex haiku-control-keysym
+@item haiku-control-keysym
+The system modifier key that will be treated as the Control key by
+Emacs.  It defaults to @code{control}.
+
+@vindex haiku-super-keysym
+@item haiku-super-keysym
+The system modifier key that will be treated as the Super key by
+Emacs.  It defaults to @code{option}.
+
+@vindex haiku-shift-keysym
+@item haiku-shift-keysym
+The system modifier key that will be treated as the Shift key by
+Emacs.  It defaults to @code{shift}.
+@end table
+
+The value of each variable can be one of the symbols @code{command},
+@code{control}, @code{option}, @code{shift}, or @code{nil}.
+@code{nil} or any other value will cause the default value to be used
+instead.
+
+@cindex tooltips (haiku)
+@cindex haiku tooltips
+@vindex haiku-use-system-tooltips
+  On Haiku, Emacs defaults to using the system tooltip mechanism.
+This usually leads to more responsive tooltips, but the tooltips will
+not be able to display text properties or faces.  If you need those
+features, customize the variable @code{haiku-use-system-tooltips} to
+the nil value, and Emacs will use its own implementation of tooltips.
+
+  Both system tooltips and Emacs's own tooltips cannot display above
+the menu bar, so help text in the menu bar will display in the echo
+area instead.
+
+@subsection What to do when Emacs crashes
+@cindex crashes, Haiku
+@cindex haiku debugger
+@vindex haiku-debug-on-fatal-error
+  If the variable @code{haiku-debug-on-fatal-error} is non-nil, Emacs
+will launch the system debugger when a fatal signal is received.  It
+defaults to @code{t}.  If GDB cannot be used on your system, please
+attach the report generated by the system debugger when reporting a
+bug.
+
+@table @code
+@vindex haiku-use-system-debugger
+@item haiku-use-system-debugger
+When non-nil, Emacs will ask the system to launch the system debugger
+whenever it experiences a fatal error.  This behaviour is standard
+among Haiku applications.
+@end table
+
+@node Haiku Fonts
+@section Font and font backend selection on Haiku
+@cindex font backend selection (Haiku)
+
+  Emacs, when built with Haiku windowing support, can be built with
+several different font backends.  You can specify font backends by
+specifying @kbd{-xrm Emacs.fontBackend:BACKEND} on the command line
+used to invoke Emacs, where @kbd{BACKEND} is one of the backends
+specified below, or on a per-frame basis by changing the
+@code{font-backend} frame parameter. (@pxref{Parameter Access,,,
+elisp, The Emacs Lisp Reference Manual}).
+
+  Two of these backends, @code{ftcr} and @code{ftcrhb} are identical
+to their counterparts on the X Window System.  There is also a
+Haiku-specific backend named @code{haiku}, that uses the App Server to
+draw fonts, but does not at present support display of color font and
+emoji.