build: Start using meson feature options

Use feature options for things that are optional features,
update the docs.

Visible changes here is that the 'print-backends' option
got renamed to 'print' to go better with 'media', and the
'tracker3' option got renamed to 'tracker'.

For options that have been changed into features, the
syntax now is -Dfeature=enabled or -Dfeature=disabled
or -Dfeature=auto.

7 files changed, 229 insertions, 181 deletions

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 391c3aacdc..2bd9ab8377 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -17,8 +17,8 @@ stages:
 # Common variables
 variables:
   COMMON_MESON_FLAGS: "--fatal-meson-warnings -Dgtk:werror=true"
-  BACKEND_FLAGS: "-Dx11-backend=true -Dwayland-backend=true -Dbroadway-backend=true -Dvulkan=yes"
-  FEATURE_FLAGS: "-Dcloudproviders=true"
+  BACKEND_FLAGS: "-Dx11-backend=true -Dwayland-backend=true -Dbroadway-backend=true"
+  FEATURE_FLAGS: "-Dvulkan=enabled -Dcloudproviders=enabled"
   MESON_TEST_TIMEOUT_MULTIPLIER: 3
   FEDORA_IMAGE: "registry.gitlab.gnome.org/gnome/gtk/fedora:v22"
   FLATPAK_IMAGE: "registry.gitlab.gnome.org/gnome/gnome-runtime-images/gnome:master"
diff --git a/.gitlab-ci/test-msys2.sh b/.gitlab-ci/test-msys2.sh
index 07f01919a7..1298ab659a 100644
--- a/.gitlab-ci/test-msys2.sh
+++ b/.gitlab-ci/test-msys2.sh
@@ -66,7 +66,7 @@ meson \
     -Dx11-backend=false \
     -Dwayland-backend=false \
     -Dwin32-backend=true \
-    -Dvulkan=no \
+    -Dvulkan=disabled \
     -Dintrospection=false \
     -Dgtk:werror=true \
     _build
diff --git a/docs/reference/gtk/building.md b/docs/reference/gtk/building.md
index 7412e25473..9092d10d1d 100644
--- a/docs/reference/gtk/building.md
+++ b/docs/reference/gtk/building.md
@@ -206,22 +206,70 @@ all else fails, you can ask for help on the
 
 ## Extra Configuration Options {#extra-configuration-options}
 
-In addition to the normal options provided by Meson,
-GTK defines various arguments that modify what should
-be built. All of these options are passed to `meson`
-as `-Doption=value`. Most of the time, the value can
-be `true` or `false`. To see a summary of all supported
-options and their allowed values, run
+In addition to the normal options provided by Meson, GTK defines various
+arguments that modify what should be built. All of these options are passed
+to `meson` as `-Doption=value`. Most of the time, the value can be `true` or
+`false`, or `enabled`, `disabled` or `auto`.
+
+To see a summary of all supported options and their allowed values, run
 ```
 meson configure builddir
 ```
 
+### `x11-backend`, `win32-backend`, `broadway-backend`, `wayland-backend` and `macos-backend`
+
+Enable specific backends for GDK.  If none of these options
+are given, the Wayland backend will be enabled by default,
+if the platform is Linux; the X11 backend will also be enabled
+by default, unless the platform is Windows, in which case the
+default is win32, or the platform is macOS, in which case the
+default is macOS. If any backend is explicitly enabled or disabled,
+no other platform will be enabled automatically.
+
+### `vulkan`
+
+By default, GTK will try to build with support for the Vulkan graphics
+API in addition to cairo and OpenGL. This option can be used to explicitly
+control whether Vulkan should be used.
+
 ### `xinerama`
 
-By default GTK will try to link against the Xinerama libraries
+By default, GTK will try to link against the Xinerama libraries
 if they are found. This option can be used to explicitly control
 whether Xinerama should be used.
 
+### `media`
+
+By default, GTK will try to build the gstreamer backend for
+media playback support. This option can be used to explicitly
+control which media backends should be built.
+
+### `print`
+
+By default, GTK will try to build various print backends
+if their dependencies are found. This option can be used
+to explicitly control which print backends should be built.
+
+### `cloudproviders`
+
+This option controls whether GTK should use libcloudproviders for
+supporting various Cloud storage APIs in the file chooser.
+
+### `sysprof`
+
+This option controls whether GTK should include support for
+tracing with sysprof.
+
+### `tracker`
+
+This option controls whether GTK should use Tracker for search
+support in the file chooser.
+
+### `colord`
+
+This option controls whether GTK should use colord for color
+calibration support in the cups print backend.
+
 ### `gtk_doc` and `man-pages`
 
 The *gtk-doc* package is used to generate the reference documentation
@@ -235,22 +283,6 @@ manual pages generated using a similar set of dependencies;
 if you have *xsltproc* then you can generate manual pages by
 passing `-Dman-pages=true` when configuring the build.
 
-### `print-backends`
-
-By default, GTK will try to build various print backends
-if their dependencies are found. This option can be used
-to explicitly control which print backends should be built.
-
-### `x11-backend`, `win32-backend`, `broadway-backend`, `wayland-backend` and `quartz-backend`
-
-Enable specific backends for GDK.  If none of these options
-are given, the Wayland backend will be enabled by default,
-if the platform is Linux; the X11 backend will also be enabled
-by default, unless the platform is Windows, in which case the
-default is win32, or the platform is macOS, in which case the
-default is quartz. If any backend is explicitly enabled or disabled,
-no other platform will be enabled automatically.
-
 ### `introspection`
 
 Allows to disable building introspection support. This is option
diff --git a/gtk/meson.build b/gtk/meson.build
index a2d9272e74..dee33baa5e 100644
--- a/gtk/meson.build
+++ b/gtk/meson.build
@@ -741,7 +741,7 @@ foreach p: proto_sources
   endif
 endforeach
 
-if os_unix and tracker3_enabled
+if os_unix and tracker3_dep.found()
   gtk_sources += 'gtksearchenginetracker3.c'
 endif
 
@@ -1023,11 +1023,9 @@ if x11_enabled or wayland_enabled
   gtk_deps += pangoft_dep
 endif
 
-if cloudproviders_enabled
-  gtk_deps += cloudproviders_dep
-endif
+gtk_deps += cloudproviders_dep
 
-if os_unix and tracker3_enabled
+if os_unix
   gtk_deps += tracker3_dep
 endif
 
diff --git a/meson.build b/meson.build
index 7d3f083a9d..8fe92ec959 100644
--- a/meson.build
+++ b/meson.build
@@ -93,7 +93,6 @@ x11_enabled      = get_option('x11-backend')
 wayland_enabled  = get_option('wayland-backend')
 broadway_enabled = get_option('broadway-backend')
 macos_enabled    = get_option('macos-backend')
-quartz_enabled   = get_option('quartz-backend')
 win32_enabled    = get_option('win32-backend')
 
 os_unix   = false
@@ -392,15 +391,11 @@ if os_unix
   platform_gio_dep = giounix_dep
 endif
 
-tracker3_enabled = get_option('tracker3')
-if tracker3_enabled
-  tracker3_dep = dependency('tracker-sparql-3.0', required: false)
-  if tracker3_dep.found()
-    cdata.set('HAVE_TRACKER3', tracker3_dep.found())
-  else
-    error('Tracker3 not found, but was explicitly requested.')
-  endif
-endif
+tracker3_dep = dependency('tracker-sparql-3.0', required: get_option('tracker'))
+cdata.set('HAVE_TRACKER3', tracker3_dep.found())
+
+colord_dep = dependency('colord', version: '>= 0.1.9', required: get_option('colord'))
+cdata.set('HAVE_COLORD', colord_dep.found())
 
 if iso_codes_dep.found()
   cdata.set_quoted('ISO_CODES_PREFIX', iso_codes_dep.get_pkgconfig_variable('prefix'))
@@ -408,6 +403,7 @@ else
   cdata.set_quoted('ISO_CODES_PREFIX', '/usr')
 endif
 
+
 backend_immodules = []
 
 pc_gdk_extra_libs = []
@@ -560,18 +556,17 @@ if x11_enabled
   # Note that we also check that the XIScrollClassInfo struct is defined,
   # because at least Ubuntu Oneiric seems to have XIAllowTouchEvents(),
   #   but not the XIScrollClassInfo struct
-  has_allow_touch_evens = cc.has_function('XIAllowTouchEvents', dependencies: xi_dep)
+  has_allow_touch_events = cc.has_function('XIAllowTouchEvents', dependencies: xi_dep)
   has_scroll_class_info = cc.has_member('XIScrollClassInfo', 'number', dependencies: xi_dep,
                                         prefix: '''#include <X11/Xlib.h>
                                                    #include <X11/extensions/XInput2.h>''')
-  if has_allow_touch_evens and has_scroll_class_info
+  if has_allow_touch_events and has_scroll_class_info
     cdata.set('XINPUT_2_2', 1)
   endif
 
-  enable_xinerama = get_option('xinerama')
-  if enable_xinerama != 'no'
-    want_xinerama = enable_xinerama == 'yes'
-    xinerama_dep = dependency('xinerama', required: want_xinerama)
+  enable_xinerama = get_option('xinerama').enabled()
+  if enable_xinerama
+    xinerama_dep = dependency('xinerama', required: true)
     if xinerama_dep.found() and cc.has_header_symbol('X11/extensions/Xinerama.h', 'XineramaQueryExtension', dependencies: xinerama_dep)
       cdata.set('HAVE_XFREE_XINERAMA', 1)
       x11_pkgs += ['xinerama']
@@ -653,89 +648,66 @@ if os_unix
 endif
 
 # Check for Vulkan support
-# TODO: move to gsk subfolder maybe? Or will it be used elsewhere too?
-have_vulkan = false
-vulkan_pkg_found = false
-vulkan_dep = []
-
-enable_vulkan = get_option('vulkan')
-if enable_vulkan == 'no'
-  message('Vulkan support explicitly disabled')
+vulkan_dep = dependency('vulkan', required: get_option('vulkan'))
+if vulkan_dep.found()
+  have_vulkan = true
+  vulkan_pkg_found = true
 else
-  vulkan_dep = dependency('vulkan', required: false)
-  if vulkan_dep.found()
-    have_vulkan = true
-    vulkan_pkg_found = true
+  have_vulkan = false
+  vulkan_pkg_found = false
+  if cc.get_id() == 'msvc'
+    vulkan_libname = 'vulkan-1'
   else
-    if cc.get_id() == 'msvc'
-      vulkan_libname = 'vulkan-1'
-    else
-      vulkan_libname = 'vulkan'
-    endif
-    vulkan_dep = cc.find_library(vulkan_libname, required: false)
-    if vulkan_dep.found() and cc.has_function('vkCreateInstance', dependencies: vulkan_dep) and cc.has_header('vulkan/vulkan.h')
-      have_vulkan = true
-      pc_gdk_extra_libs += ['-l@0@'.format(vulkan_libname)]
-    endif
+    vulkan_libname = 'vulkan'
   endif
-  if enable_vulkan == 'yes' and not have_vulkan
-    error('Vulkan support not found, but was explicitly requested.')
+  vulkan_dep = cc.find_library(vulkan_libname, required: false)
+  if vulkan_dep.found() and cc.has_function('vkCreateInstance', dependencies: vulkan_dep) and cc.has_header('vulkan/vulkan.h')
+    have_vulkan = true
+    pc_gdk_extra_libs += ['-l@0@'.format(vulkan_libname)]
   endif
 endif
 
-cloudproviders_enabled = get_option('cloudproviders')
-if cloudproviders_enabled
-  cloudproviders_dep = dependency('cloudproviders',
-    version: cloudproviders_req,
-    fallback: [
-      'libcloudproviders',
-      'libcloudproviders_dep',
-    ],
-    default_options: [
-      'vapigen=false',
-    ])
-  if cloudproviders_dep.found()
-    cdata.set('HAVE_CLOUDPROVIDERS', cloudproviders_dep.found())
-  else
-    error('Cloudproviders support not found, but was explicitly requested.')
-  endif
-endif
+cloudproviders_dep = dependency('cloudproviders',
+  required: get_option('cloudproviders'),
+  version: cloudproviders_req,
+  fallback: [
+    'libcloudproviders',
+    'libcloudproviders_dep',
+  ],
+  default_options: [
+    'vapigen=false',
+  ])
+cdata.set('HAVE_CLOUDPROVIDERS', cloudproviders_dep.found())
 
 profiler_enabled = get_option('sysprof').enabled()
-if profiler_enabled
-  # libsysprof-capture support
-  libsysprof_capture_dep = dependency('sysprof-capture-4',
-    required: true,
-    default_options: [
-      'enable_examples=false',
-      'enable_gtk=false',
-      'enable_tests=false',
-      'enable_tools=false',
-      'libsysprof=true',
-      'with_sysprofd=none',
-      'help=false',
-    ],
-    fallback: ['sysprof', 'libsysprof_capture_dep'],
-  )
-  if libsysprof_capture_dep.found()
-    cdata.set('HAVE_SYSPROF', 1)
-  else
-    error('Profiler support not found, but was explicitly requested.')
-  endif
-  libsysprof_dep = dependency('sysprof-4',
-    required: false,
-    default_options: [
-      'enable_examples=false',
-      'enable_gtk=false',
-      'enable_tests=false',
-      'enable_tools=false',
-      'libsysprof=true',
-      'with_sysprofd=none',
-      'help=false',
-    ],
-    fallback: ['sysprof', 'libsysprof_dep'],
-  )
-endif
+# libsysprof-capture support
+libsysprof_capture_dep = dependency('sysprof-capture-4',
+  required: get_option('sysprof'),
+  default_options: [
+    'enable_examples=false',
+    'enable_gtk=false',
+    'enable_tests=false',
+    'enable_tools=false',
+    'libsysprof=true',
+    'with_sysprofd=none',
+    'help=false',
+  ],
+  fallback: ['sysprof', 'libsysprof_capture_dep'],
+)
+cdata.set('HAVE_SYSPROF', libsysprof_capture_dep.found())
+libsysprof_dep = dependency('sysprof-4',
+  required: false,
+  default_options: [
+    'enable_examples=false',
+    'enable_gtk=false',
+    'enable_tests=false',
+    'enable_tools=false',
+    'libsysprof=true',
+    'with_sysprofd=none',
+    'help=false',
+  ],
+  fallback: ['sysprof', 'libsysprof_dep'],
+)
 
 graphene_dep_type = graphene_dep.type_name()
 if graphene_dep_type == 'pkgconfig'
@@ -889,10 +861,12 @@ endif
 summary('Display backends', display_backends)
 summary('Print backends', print_backends)
 summary('Media backends', media_backends)
-summary('Vulkan support', have_vulkan)
-summary('Cloud support', get_option('cloudproviders'))
-summary('Sysprof support', get_option('sysprof').enabled())
-summary('Colord support', get_option('colord'))
+
+summary('Vulkan support', vulkan_dep.found(), section: 'Features')
+summary('Cloud support', cloudproviders_dep.found(), section: 'Features')
+summary('Sysprof support', libsysprof_capture_dep.found(), section: 'Features')
+summary('Colord support', colord_dep.found(), section: 'Features')
+summary('Tracker support', tracker3_dep.found(), section: 'Features')
 
 # Build
 summary('Debugging', get_option('debug'), section: 'Build')
diff --git a/meson_options.txt b/meson_options.txt
index 5eb0a6087e..f4dc3b43d7 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -1,57 +1,111 @@
 # GDK backends
-option('x11-backend', type: 'boolean', value: true,
-  description : 'Enable the X11 gdk backend (only when building on Unix)')
-option('wayland-backend', type: 'boolean', value: true,
-  description : 'Enable the wayland gdk backend (only when building on Unix except for macOS)')
-option('broadway-backend', type: 'boolean', value: false,
-  description : 'Enable the broadway (HTML5) gdk backend')
-option('win32-backend', type: 'boolean', value: true,
-  description : 'Enable the Windows gdk backend (only when building on Windows)')
-option('quartz-backend', type: 'boolean', value: true,
-  description : 'Enable the macOS gdk backend (only when building on macOS)')
-option('macos-backend', type: 'boolean', value: true,
-  description : 'Enable the macOS gdk backend (only when building on macOS)')
+
+option('x11-backend',
+       type: 'boolean',
+       value: true,
+       description : 'Enable the X11 gdk backend (only when building on Unix)')
+
+option('wayland-backend',
+       type: 'boolean',
+       value: true,
+       description : 'Enable the wayland gdk backend (only when building on Unix except for macOS)')
+
+option('broadway-backend',
+       type: 'boolean',
+       value: false,
+       description : 'Enable the broadway (HTML5) gdk backend')
+
+option('win32-backend',
+       type: 'boolean',
+       value: true,
+       description : 'Enable the Windows gdk backend (only when building on Windows)')
+
+option('macos-backend',
+       type: 'boolean',
+       value: true,
+       description : 'Enable the macOS gdk backend (only when building on macOS)')
 
 # Media backends
-option('media', type: 'string', value: 'gstreamer',
-  description : 'Build the specified media engines (comma-separated list, "all", or "none")')
 
-# Optional dependencies
-option('vulkan', type: 'combo', choices : ['yes', 'no', 'auto'], value : 'auto',
-  description : 'Enable support for the Vulkan graphics API')
-option('xinerama', type: 'combo', choices : ['yes', 'no', 'auto'], value : 'auto',
-  description : 'Enable support for the Xinerama extension')
-option('cloudproviders', type: 'boolean', value: false,
-  description : 'Enable the cloudproviders support')
+option('media',
+       type: 'string',
+       value: 'gstreamer',
+       description : 'Build the specified media engines (comma-separated list, "all", or "none")')
+
+# Print backends
+
+option('print',
+       type: 'string',
+       value: 'cups,file',
+       description : 'Build the specified print backends (comma-separated list, "all", or "none")')
+
+# Optional features
+
+option('vulkan',
+       type: 'feature',
+       value: 'enabled',
+       description : 'Enable support for the Vulkan graphics API')
+
+option('xinerama',
+       type: 'feature',
+       value: 'enabled',
+       description : 'Enable support for the X11 Xinerama extension')
+
+option('cloudproviders',
+       type: 'feature',
+       value: 'disabled',
+       description : 'Enable the cloudproviders support')
 
 option('sysprof',
        type: 'feature',
        value: 'disabled',
        description : 'include tracing support for sysprof')
 
-option('tracker3', type: 'boolean', value: false,
-  description : 'Enable Tracker3 filechooser search')
+option('tracker',
+       type: 'feature',
+       value: 'disabled',
+       description : 'Enable Tracker3 filechooser search')
 
-# Print backends
-option('print-backends', type : 'string', value : 'cups,file',
-  description : 'Build the specified print backends (comma-separated list, "all", or "none")')
-option('colord', type: 'combo', choices : ['yes', 'no', 'auto'], value : 'auto',
-  description : 'Build colord support for the CUPS printing backend')
+option('colord',
+       type: 'feature',
+       value : 'disabled',
+       description : 'Build colord support for the CUPS printing backend')
 
 # Documentation and introspection
-option('gtk_doc', type: 'boolean', value: 'false',
-  description : 'Build API reference and tools documentation')
-option('man-pages', type: 'boolean', value: 'false',
-  description : 'Build man pages for installed tools')
-option('introspection', type: 'boolean', value: 'true',
-  description : 'Build introspection data (requires gobject-introspection)')
-
-# Demos and binaries
-option('demos', type: 'boolean', value: 'true',
-  description : 'Build demo programs')
-option('build-examples', type: 'boolean', value: 'true',
-  description : 'Build examples')
-option('build-tests', type: 'boolean', value: 'true',
-  description : 'Build tests')
-option('install-tests', type: 'boolean', value: 'false',
-  description : 'Install tests')
+
+option('gtk_doc',
+       type: 'boolean',
+       value: 'false',
+       description : 'Build API reference and tools documentation')
+
+option('man-pages',
+       type: 'boolean',
+       value: 'false',
+       description : 'Build man pages for installed tools')
+
+option('introspection',
+       type: 'boolean',
+       value: 'true',
+       description : 'Build introspection data (requires gobject-introspection)')
+
+# Demos, examples and tests
+
+option('demos',
+       type: 'boolean',
+       value: 'true',
+       description : 'Build demo programs')
+
+option('build-examples',
+       type: 'boolean',
+       value: 'true',
+       description : 'Build examples')
+
+option('build-tests',
+       type: 'boolean',
+       value: 'true',
+       description : 'Build tests')
+
+option('install-tests',
+       type: 'boolean',
+       value: 'false',
+       description : 'Install tests')
diff --git a/modules/printbackends/meson.build b/modules/printbackends/meson.build
index 40a9379b47..1cde173493 100644
--- a/modules/printbackends/meson.build
+++ b/modules/printbackends/meson.build
@@ -3,7 +3,7 @@ all_print_backends = [
   'cloudprint',
 ]
 
-enabled_print_backends = get_option('print-backends').split(',')
+enabled_print_backends = get_option('print').split(',')
 
 if enabled_print_backends.contains('none')
   enabled_print_backends = []
@@ -54,16 +54,6 @@ printbackends_install_dir = join_paths(get_option('libdir'), printbackends_subdi
 
 cdata.set_quoted('GTK_PRINT_BACKENDS', ','.join(print_backends))
 
-
-enable_colord = get_option('colord')
-if enable_colord != 'no'
-  want_colord = enable_colord == 'yes'
-  colord_dep = dependency('colord', version: '>= 0.1.9', required: want_colord)
-  cdata.set('HAVE_COLORD', colord_dep.found())
-else
-  colord_dep = []
-endif
-
 printbackends_args = [
   '-DGTK_COMPILATION',
   '-DGTK_DISABLE_DEPRECATION_WARNINGS',