Stop using gtk-doc, and switch to gi-docgen.
The gi-docgen tool generates API references through the introspection
data, which has various benefits:
- it does not parse C code
- it does not generate and run C code to introspect types at build time
- it does not present a different API from the one we're exporting
Additionally, gi-docgen:
- does not generate DocBook XML in order to generate HTML
- does not go through xsltproc
- parses proper Markdown
Which makes it markedly faster than gtk-doc has ever been.
Similar to e89fcbfad6
but the tests we use mallinfo() in really aren't important to not worth
the effort to differentiate between mallinfo and mallinfo2. Only check
for mallinfo2().
GModule requires the .so file extension on macOS for historic reasons.
However Meson defaults to .dylib for modules, so we need to override
it to get the correct extension.
Fixes#3645.
When I added the sassc option, I failed to ensure that
the theme css is included in the tarballs. This is required
to make tarball builds with -Dsassc=disabled work.
Most of this is cribbed from glib.
We don't use COMMON_MESON_FLAGS here, since disabling
-Werror one subproject at a time is too painful for
all the promoted sub-sub-projects. This needs a better
solution in meson.
Since this is a full rebuild of the entire stack, limit
this to master and merge requests.
Using the module will prevent trivial bugs caused by incorrect string concatenation.
This is just a literal translation. In the future we might rely on Meson auto-detecting fields from library declaration.
Fixes: https://gitlab.gnome.org/GNOME/gtk/-/issues/3517
We released all the 3.9x development snapshots using:
libgtk-4.0.so.0.xxxx.y
which means that the 4.0.0 release of GTK will have a lower SONAME than
the snapshots. To avoid that, bump the SONAME to 1.xxxx.y.
Fixes: #3392
We don't want to increase the interface age manually, because we're
going to end up forgetting about it.
Instead, we should tie it to the rest of the version:
- in stable (even minor) cycles, we don't add new API; the interface
age is the same as the micro version
- in unstable (odd minor) cycles, every new release might have new API,
or updates to newly added API; keep the interface age to 0
This removes one more manual thing to change during release, and keeps
us honest with our promise not to add symbols during stable cycles.
There is no reason to fallback to find_library for cairo and still rely
on pkg-config for all other dependencies, and just when using MSVC. When
building and pkg-config is not working it is preferable to fallback to a
subproject just like for all other dependencies.
Also add cairo.wrap now that meson support has been merged upstream.
epoxy_dep cannot be used in a configure time check when it comes from a
subproject. Use variables set in pc file instead.
This requires https://github.com/anholt/libepoxy/pull/231.
Either we or clang needs to get its shit together about this warning.
But using it during development with clang just makes actually usable
warnings get lost in a flood of -Wcast-align warnings.
For the various uses of GDK_WINDOWING_QUARTZ, we need to use
alternatives from GDK_WINDOWING_MACOS.
Some minor loss of functionality is here, such as icons sent with
application menus. That can certainly be added back at a future
point.
Yielding option means that if pango is built as a subproject, it will
take the value of that option from the parent project (e.g. gst-build).
For that to work it must be of the same type, which is "feature" instead
of "boolean" in all GStreamer modules.
Look at the languages supported by a font, and pick
a suitable sample text from the pango list of sample
texts. We can only implement this on platforms using
fontconfig, since it relies on pangofc apis.
This bumps the pango dependency to 1.47.1.
We want to include the gtk-doc subproject in release
tarballs, using --include-subprojects, but that only
works if we've actually built the subproject. And
enabling gtk-doc for dist builds is problematic -
it tends to break meson dist.
So declare the gtk-doc dependency independent of
-Dgtk_doc, and use --force-fallback-for for it.
The dependency block was completely wrong. It was:
1. Not searching for the lib manually when -Dvulkan=enabled (default).
The else block was only hit when -Dvulkan=auto.
2. Unconditionally searching for the vulkan library in the else block
when -Dvulkan=disabled
The manual searching is also not required because Meson has a custom
'vulkan' dependency class that already supports Windows, and is more
correct than the code here. Specifically, the current code does not
support picking up the Vulkan SDK from a custom path.
Fixes#3108
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.
We don't support any profilers other than sysprof,
so name the option accordingly. While we are at it,
change it to a meson feature option, so
-Dprofiler=true becomes -Dsysprof=enabled
Instead of using sysprof-cli to profile subprocesses, this uses
libsysprof's SysprofProfiler directly so that we can avoid an indirect
subprocess as well as disabling the polkit nag.
To do this, we have to link against libsysprof instead of
libsysprof-capture. This is limited to the -Dbuild-tests=true and
-Dprofiler=true case.
...EGL support needs to be explicitly enabled during the build of
libepoxy on Windows as it is not enabled by default on Windows.
With this, we can add an EGL renderer for Windows that make use of
Google's libANGLE, which is a library that translates OpenGL/ES calls
to Direct3D 9/11, which will provide better hardware compatibility
on Windows and would act as one of the foundations to resolve issue #105.
Sysprof has moved to a new ABI which removes GLib from the capture library
so that GLib itself can link against sysprof-capture.
This bumps the library ABI so we can keep things coordinated between all
the new tracing layers in the stack.
When converting DisplayLink frame presentation times, we need to take into
account the arch-specific types. This tracks changes in GNOME/GLib!1566 so
that precision is not lost.
To build a better world sometimes means having to tear the old one down.
-- Alexander Pierce, "Captain America: The Winter Soldier"
ATK served us well for nearly 20 years, but the world has changed, and
GTK has changed with it. Now ATK is mostly a hindrance towards improving
the accessibility stack:
- it maps to a very specific implementation, AT-SPI, which is Linux and
Unix specific
- it requires implementing the same functionality in three different
layers of the stack: AT-SPI, ATK, and GTK
- only GTK uses it; every other Linux and Unix toolkit and application
talks to AT-SPI directly, including assistive technologies
Sadly, we cannot incrementally port GTK to a new accessibility stack;
since ATK insulates us entirely from the underlying implementation, we
cannot replace it piecemeal. Instead, we're going to remove everything
and then incrementally build on a clean slate:
- add an "accessible" interface, implemented by GTK objects directly,
which describe the accessible role and state changes for every UI
element
- add an "assistive technology context" to proxy a native accessibility
API, and assign it to every widget
- implement the AT context depending on the platform
For more information, see: https://gitlab.gnome.org/GNOME/gtk/-/issues/2833
This is fairly substantial rewrite of the GDK backend for quartz and
renamed to macOS to allow for a greenfield implementation.
Many things have come across from the quartz implementation fairly
intact such as the eventloop integration design and discovery of
event windows from the NSEvent.
However much has been changed to fit in with the new GDK design and
how removal of child GdkWindow have been completely eliminated.
Furthermore, the new GdkPopup allows for regular NSWindow to be used
to provide popovers unlike the previous implementation.
The object design more closely follows the ideal for a GDK backend.
Views have been broken out into subclasses so that we can support
multiple GSK renderer paths such as GL and Cairo (and Metal in the
future). However mixed mode GL and Cairo will not be supported. Currently
only the Cairo renderer has been implemented.
A new frame clock implementation using CVDisplayLink provides more
accurate information about when to draw drawing the next frame. Some
testing will need to be done here to understand the power implications
of this.
This implementation has also gained edge snapping for CSD windows. Some
work was also done to ensure that CSD windows have opaque regions
registered with the display server.
** This is still very much a work-in-progress **
Some outstanding work that needs to be done:
- Finish a GL context for macOS and alternate NSView for GL rendering
(possibly using speciailized CALayer for OpenGL).
- Input rework to ensure that we don't loose remapping of keys that was
dropped from GDK during GTK 4 development.
- Make sure input methods continue to work.
- Drag-n-Drop is still very much a work in progress
- High resolution input scrolling needs various work in GDK to land
first before we can plumb that to NSEvent.
- gtk/ has a number of things based on GDK_WINDOWING_QUARTZ that need
to be updated to use the macOS backend.
But this is good enough to start playing with and breaking things which
is what I'd like to see.
This was preventing any sort of building on macOS, even though the quartz
backend is currently non-functional. Fixing this is a pre-requisite to
getting a new macOS backend compiling.
commit 14bf58ec5d dropped support
for using the DAMAGE extension since there was no code that
needed it.
We're going to need it again, however, to address an NVidia
vendor driver issue.
This commit does the plumbing to add it back.
Visual Studio does not allow decorating functions with '__declspec (dllexport)'
if a prototype exists and is not decorated with '__declspec (dllexport)' as
well, so we cannot just decorate g_io_module_[load|unload|query] in the various
module sources with G_MODULE_EXPORT because the prototypes of these functions
have been marked with _GLIB_EXTERN, which equates to 'extern' unless overridden
Fix this by overriding _GLIB_EXTERN with the appropriate visibility flag, as we
have used to define _GDK_EXTERN. Unfortunately, we can't just use _GDK_EXTERN
G_MODULE_EXPORT as they may have not been defined yet for our use
Do this across the board for all modules, even if they are not buildable on
Visual Studio nor Windows, for consistency's sake.
We require a C compiler supporting C99 now. The main purpose of
these fallbacks was for MSVC. From what I can see this is now all supported
by MSVC 2015+ anyway.
The only other change this includes is to replace isnanf() with the
(type infering) C99 isnan() macro, because MSVC doesn't provide isnanf().
We were applying the pango version requirements inconsistently,
leading to different pango variables being taking from system
pango vs the subproject at times. Thankfully, meson detects
this and complains, so we can fix it.
We soon want to rely on the list model apis in
pango 1.45. This commit also fixes a mixup where
using pango as a submodule would break the build
when pangoft2 is required.
We soon want to rely on the list model apis in
pango 1.45. This commit also fixes a mixup where
using pango as a submodule would break the build
when pangoft2 is required.
Path concatenation is much nicer than the unwieldy format method.
Since paths returned by get_option are relative to prefix, they will be joined as before.
As a bonus, this fixes weird platforms like NixOS that actually pass absolute includedir under a different prefix.
Set version and soversion separately for the library.
When we do the 4.0 release, we will set:
gtk_soversion = '1'
gtk_library_version = '1.0.0'
See https://gitlab.gnome.org/GNOME/gtk/-/issues/1963
The third version of xdg-shell introduces support for explicit popup
repositioning. If available, make use of this to implement popup
repositioning.
Note that this does *NOT* include atomic parent-child state
synchronization. For that,
https://gitlab.freedesktop.org/wayland/wayland-protocols/issues/13 will
be needed.
This currently uses my own fork of wayland-protocols which adds meson
support, so that we can use it as a subproject. Eventually when
wayland-protocols' meson support lands upstream, we should change it to
point there.
Silence some meson warnings while at it to make CI happy.
This also bumps the glib requirement, since g_warning_once() is used.
`get_option('buildtype')` will return `'custom'` for most combinations
of `-Doptimization` and `-Ddebug`, but those two will always be set
correctly if only `-Dbuildtype` is set. So we should look at those
options directly.
For the two-way mapping between `buildtype` and `optimization`
+ `debug`, see this table:
https://mesonbuild.com/Builtin-options.html#build-type-options
In addition to the traditional library directory lib and the 64-bit
multilib directory lib64, this will cover Debian-style multiarch
(lib/x86_64-linux-gnu etc.), Arch Linux 32-bit (lib32), x32 and
various others.
Signed-off-by: Simon McVittie <smcv@debian.org>
Sprinkle various g_assert() around the code where gcc cannot figure out
on its own that a variable is not NULL and too much refactoring would be
needed to make it do that.
Also fix usage of g_assert_nonnull(x) to use g_assert(x) because the
first is not marked as G_GNUC_NORETURN because of course GTester
supports not aborting on aborts.
This avoids the build from erroring out on C4819 (Unicode handling issue in
Visual Studio compiler), notably when running on Chinese, Japanese and
Korean locales.
Also apply -D_USE_MATH_DEFINES, -FImsvc_recommended_pragmas.h and -utf-8 to
the C++ compiler options as well.
Copy just enough of libwayland-cursor to make our own
loading. This lets us drop the dependency on libwayland-cursor,
and changes the startup cost for cursor theme loading
from 25ms to 0.1ms.
At the same time, simplify the handling of scaled cursors -
instead of creating an array of theme objects, just make a
single theme object provide all scaled cursor sizes.
sincosf() is really a GCC-specific function that may more may not be
supported on non-GCC compilers, so we want to check for it, otherwise we
use a fallback implementation, not unlike the one in
demos/gtk-demo/gtkgears.c.
The `name` and `description` events were added to `xdg-output` protocol
in version 2 which is part of wayland-protocols 1.14.
In xdg-output-v1 version 3, the `xdg-output.done` event was deprecated
and the `xdg-output.description` event was made mutable, but that
doesn't change the actual events so we do not actually need to require
that version of xdg-output from wayland-protocols 1.18.
Update the wayland-protocols requirement to the bare minimum version,
which is 1.14.
https://gitlab.gnome.org/GNOME/gtk/issues/2057
Use cairo-script-interpreter to parse the scripts that generate cairo
nodes.
This requires libcairoscriptinterpreter.so to work properly, but if
it isn't found we disable this (unimportant for normal functioning)
code and just emits a parser warning.
The testsuite requires it however or it will fail.
A new test is included that tests all of this.
This uses the new sysprof-3 ABI to implement the capture writer. It also
uses the statically linked libsysprof-capture-3.a that is provided with
Sysprof for the capture writing to ensure that we do not leak any symbols
nor depend on any additional libraries.
The GTK_TRACE_FD can be used to pass a FD for tracing into Gtk. Sysprof
uses this when the Gtk instrument is selected for recording.
The 'documentation' option also guarded the man page build. Instead
if skipping the whole docs subdir skip the specific gtkdoc calls, so that the
man page build still works.
This brings it in line with the gtk3 meson build.
XInput2 is more than a decade old already, and the input improvements
there (and in every other backend really) make it untenable to have
support for X11 core input events dragging things behind.
Added two new private GtkWidget API:
* gtk_widget_add_surface_transform_changed_callback()
* gtk_widget_remove_surface_transform_changed_callback()
The intention is to let the user know when a widget transform relative
to the surface changes. It works by calculating the surface relative
transform during allocation, and notifying the callbacks if it changed
since last time. Each widget adds itself as a listener to its parent
widget, thus will be triggered if a parents surface relative transform
changes.
These flags check for code that we don't want to write, so turn them
into error flags.
Variable length arrays should be replaced by malloc() - or explicit
alloca() calls if you know what you're doing.
Implicit fallthrough should be replaced by explicit fallthrough with the
usage of G_GNU_FALLTHROUGH.
This work inspired by Kees Cook's LCA2019 talk:
https://www.youtube.com/watch?v=FY9SbqTO5GQhttp://outflux.net/slides/2019/lca/danger.pdf
This library is meant to be the new CSS library that gets used from GDK,
GSK and GTK for string printing and parsing.
As a first step, move GtkCssProviderError into it.
While doing so, split it into GtkCssParserError (for critical problems)
and GtkCssParserWarning (for non-critical problems).
The current Meson releases have broken CMake support, meaning that it is
likely that HarfBuzz could not be located for Visual Studio builds
unless one handcrafts pkg-config files for it, which is both tedious and
error-prone.
Instead, use the existing mechanism for looking for the HarfBuzz headers
and libraries on Visual Studio first when it could not be found via
dependency(), and then use the fallback if it still could not be found.
In particular, check that to_matrix() and to_2d(), to_affine() and
to_translate() return the same values.
This also requires a recent Graphene version or the tests will fail.
The tests were added when we thought we had to align memory allocations
for structures including a Graphene type in their members. Graphene
added alignment annotations for its types, and we never really used the
symbols we set after testing for allocations being aligned out of the
box with malloc(), and for aligned allocators.
Some of the flags got lost in the meson transition or were demoted from
error flags to warning flags.
This commit reintroduces them.
It also includes fixes for the code that had warnings with those flags.
The big one being -Wshadow.
Using an empty `configuration_data` object to copy a configuration file
is deprecated since Meson 0.47 (released July 2018); the equivalent
behaviour is available by using `copy: true`.
The existing post-install shell script will most likely not work on
Visual Studio builds as there is normally no shell interpreter installed
on the system where the build is done, but the build is normally done in
a standard Windows cmd.exe console.
Instead, use a Python script so that it will work on the platforms that
Python supports.
This meson port is not upstream yet, so a wrap file is not included.
Upstream has expressed interest but the port hasn't been tested on all
platforms yet. Will be added when it gets upstreamed.
Link to WIP port: https://github.com/centricular/harfbuzz
* A bunch of new variables for config.h.meson
* A check for aligned allocation being necessary at all
(graphene must use GCC vector instructions or SSE2)
* A check for C malloc() being aligned at 16-byte boundaries
* A check for a few special aligned allocator functions being
present and not being built-ins (posix_memalign is a builtin
in GCC, even on platforms where there is no posix_memalign
system function)
* Added -mstackrealign flag on Windows, since otherwise
stack variables may become unaligned when the stack briefly
passes through OS code (such as in various callbacks and
handlers)
The header linux/input.h used by GDK is specific to Linux. It is
possible to get a few Linux headers on FreeBSD by installing v4l_compat,
but it is usually better to use the one shipped with FreeBSD.
We prefer dev/evdev/input.h to linux/input.h here, so it will always use
dev/evdev/input.h on FreeBSD regardless of v4l_compat.
https://svnweb.freebsd.org/changeset/ports/465644
This commit adds support the stable version of the xdg-shell protocol.
Support for the last version of the unstable series is left intact, but
will not receive new features.
The stable version is prioritized above the older version.
https://bugzilla.gnome.org/show_bug.cgi?id=791939
Instead of hard-coding linker flags for a specific operating system and
a specific compiler, we can should cc.links to test them, so they can be
used on more operating systems and compilers.
All of the four platform-dependent backends are enabled by default. It
is usually a good default because it requires users to explicitly choose
backends they want to use. Rules in meson.build also automatically
disable unavailable backends for macOS, Windows, Linux, so users on
these 3 major platforms don't have to manually disable things when
running meson commands.
However, meson.build doesn't do the same thing for other Unix-like
systems, which is acceptable but not ideal. To make it easier to build
GTK+ on these systems, the Linux case, which enables X11 and Wayland and
disables Win32 and Quartz, is made the default for all operating systems
that are not Windows or macOS.
This commit also changes most 'host_machine.system()' calls to os_*
variables, which are easier to read and less likely to be used wrongly.
Instead of going through an ancillary script to strip away the
`WL_EXPORT` annotation from the generated code, we should bump up the
required version of Wayland, and use the `private-code` argument for
wayland-scanner, which does the right thing for us.
The demos are now built as GUI programs, which will require the presence
of WinMain() on Visual Studio builds, unless we specify the entry point.
Pass the /entry:mainCRTStartup linker flag on Visual Studio builds for
the demo programs so that they can link properly.
https://bugzilla.gnome.org/show_bug.cgi?id=773299
Examples are not like demos; the latter are installed, and provide a
Flatpak manifest for CI pipelines and GNOME Builder. We should not be
using a single configure time option to gate building both.
We forgot to account for the case where we lookup for HarfBuzz manually
under Visual Studio builds, so only set HAVE_HARFBUZZ (and thus
HAVE_PANGOFT, since PangoFT2 depends on HarfBuzz) after we did the
fallback check for HarfBuzz.
Also, check for hb.h instead of harfbuzz/hb.h to be inline with the
pkg-config case, as the sources also include the HarfBuzz header by
using #include <hb.h>, not #include <harfbuzz/hb.h>
https://bugzilla.gnome.org/show_bug.cgi?id=773299
Check for freetype2 version, because pangoft works with any version
(pangoft availability does not indicate that ft2 is new enough), unlike
GTK.
On Windows, since pangoft is optional, we check for the presence of
freetype2 .pc file first after finding that we have pangoft, and then
check for FT_Get_Var_Design_Coordinates() manually by looking for the
freetype headers and .lib first, and then looking for the presence of
that symbol, since freetype2's Visual Studio build system does not
generate a .pc file for us.
https://bugzilla.gnome.org/show_bug.cgi?id=773299
Meson warns when doing that, as it's not really portable.
Since we're using platform-specific linker flags on Darwin, we can also
do the same on Linux; the syntax is GCC-specific, so we're going to need
Clang users to test it.
This way, we can support external libraries providing implementations of
GtkMediaFile.
We also add a media backend called 'nomedia' that can be enabled to not
compile any support for GtkMediaFile. This is useful when people want to
statically compile GTK into an application that does not use media.
For now, this option is the default.
We also support a new environment variable GTK_MEDIA that allows
selecting the implementation to use.
GTK_MEDIA=help can be used to get info about the available
implementations.
This makes demos be compiled/linked before tests. And that means that
while hacking, I can already run widget-factory when the tests are
still linking.
Release builds should only disable cast checks, to match what we used
to do back with the Autotools builds.
The Autotools build had an "--enable-debug=no" option, but that was
rarely used; Meson has debug, debugoptimized, release, and plain build
types, but we considered the "release" build types as the old "disable
all debugging code", which is not really accurate.
Disabling assertions and preconditon checks should be left to people
with constrained environments and/or packagers; they are supposed to
use the "plain" build type, and override the CFLAGS themselves.
Drop the 'enable-' prefix, and always enable all platform-specific
backends. We can disable them depending on the platform. This way,
the documentation printed by `meson configure` remains accurate.
Instead of having separate options for each print backend, we can use
the same approach as the input method modules: a single option, with a
comma-separated list of print backends.
The standard Vulkan SDK ships with a pkg-config file, like a modern
library should.
We should fall back to finding the library and header only for platforms
where pkg-config is not really a thing.
Based on a patch by: Daniel Stone <daniels@collabora.com>
https://bugzilla.gnome.org/show_bug.cgi?id=793181
Add the necessary machinery into the Meson definition files so that we
can build for Windows.
Since we don't have Wayland or X support for our use case here, disable
them once we know that we are building for Windows, as they are
(otherwise) enabled by default, and enable the items that need to be
built for Windows builds.
Exclude gtk4-launch from Windows builds as that is something that
is not supported on Windows.
As we won't have gio-unix on Windows, and PangoFT2 is optional, don't use
fallbacks for them when we are on Windows (but do use fallbacks for
gio-win32, as it will be used).
Also, clean up meson.build a bit as we can just force-include
msvc_recommended_pragmas.h from GLib since we depend on GLib, and so we
can handle these warnings from msvc_recommended_pragmas.h instead.
https://bugzilla.gnome.org/show_bug.cgi?id=785210
This patch makes that work using 1 of 2 options:
1. Add all missing enums to the switch statement
or
2. Cast the switch argument to a uint to avoid having to do that (mostly
for GdkEventType).
I even found a bug while doing that: clearing a GtkImage with a surface
did not notify thae surface property.
The reason for enabling this flag even though it is tedious at times is
that it is very useful when adding values to an enum, because it makes
GTK immediately warn about all the switch statements where this enum is
relevant.
And I expect changes to enums to be frequent during the GTK4 development
cycle.
-Wshadow these days does not overwarn anymore like it did in gcc 4.
There are no warnings inside gtk, so better enable it to keep it that
way.
-Wuninitialized also has no positives, so I'm gonna turn it on just
because.
-Wint-conversion is important because it checks casts from ints to
pointers.
-Wdiscarded-qualifiers is important to catch cases where we don't
strings when we should.
Otherwise it fails to build with:
FAILED: gtk/im-ipa@sha/imipa.c.o
...
In file included from ../gtk/gtkintl.h:4:0,
from ../modules/input/imipa.c:28:
/opt/include/glib-2.0/glib/gi18n-lib.h:27:2: error: #error You must
define GETTEXT_PACKAGE before including gi18n-lib.h. Did you
forget to include config.h?
#error You must define GETTEXT_PACKAGE before
including gi18n-lib.h. Did you forget to include config.h?
^~~~~
../modules/input/imipa.c:144:3: error: ‘GETTEXT_PACKAGE’ undeclared
here (not in a function)
GETTEXT_PACKAGE, /* Translation domain */
^~~~~~~~~~~~~~~
../modules/input/imipa.c:145:4: error: ‘GTK_LOCALEDIR’ undeclared
here (not in a function)
GTK_LOCALEDIR, /* Dir for bindtextdomain (not strictly
needed for "gtk+") */
^~~~~~~~~~~~~
For dependencies that do not generate pkg-config files for their Visual
Studio build systems, we need to look for them using cc.has_header() and
cc.find_library(), namely for Cairo and HarfBuzz, if one does not have
crafted pkg-config files for them (which, by themselves may be
error-prone).
As a result, we will still try to look for Cairo and HarfBuzz using
pkg-config, but will give another shot at them on Visual Studio using
cc.has_header() and cc.find_library() if they couldn't be found via
pkg-config.
https://bugzilla.gnome.org/show_bug.cgi?id=785210
The Vulkan .lib file that is supplied by the LunarG Vulkan SDK is
vulkan-1.lib, not vulkan.lib, so make sure we look for the right
libraries when building on Visual Studio (I am not sure whether the
LunarG SDK will work for MinGW/mingw-w64 builds, as only Visual Studio
.lib files are provided).
Note that this will require one to set LIB and INCLUDE appropriately to
find the Vulkan .lib and header files, and possibly PATH if one's video
drivers do not contain the Vulkan runtime DLL.
https://bugzilla.gnome.org/show_bug.cgi?id=785210
