meson: Use libyaml wrap file from wrapdb

Use the libyaml wrap file from the meson wrapdb instead of
creating the wrap file manually and using the cmake module.
This provides better integration with meson, such as the
`force_fallback_for` built-in option.

This is also needed because the upstream CMakeLists.txt is
out of date, failing with a sufficiently new cmake version:

    CMake Error at CMakeLists.txt:2 (cmake_minimum_required):
    Compatibility with CMake < 3.5 has been removed from CMake.

The above is nonetheless addressed by https://github.com/yaml/libyaml/pull/314,
but the project seems a bit inactive at the moment.

The wrap file was added using `meson wrap install libyaml`,
and it can be updated using `meson wrap update libyaml`.

`default_library=static` is used to match the behaviour of the
previously used cmake build. `werror=false` needs to be set
because libyaml does not compile without warnings, and that
would abort the build process otherwise.

Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>

src/libcamera/meson.build

@@ -84,7 +84,10 @@ if not cc.has_function('dlopen')
     libdl = cc.find_library('dl')
 endif
 libudev = dependency('libudev', required : get_option('udev'))
-libyaml = dependency('yaml-0.1', required : false)
+libyaml = dependency('yaml-0.1', default_options : [
+    'default_library=static',
+    'werror=false',
+])
 
 # Use one of gnutls or libcrypto (provided by OpenSSL), trying gnutls first.
 libcrypto = dependency('gnutls', required : false)
@@ -120,17 +123,6 @@ if libudev.found()
     ])
 endif
 
-# Fallback to a subproject if libyaml isn't found, as it's not packaged in AOSP.
-if not libyaml.found()
-    cmake = import('cmake')
-
-    libyaml_vars = cmake.subproject_options()
-    libyaml_vars.add_cmake_defines({'CMAKE_POSITION_INDEPENDENT_CODE': 'ON'})
-    libyaml_vars.append_compile_args('c', '-Wno-unused-value')
-    libyaml_wrap = cmake.subproject('libyaml', options : libyaml_vars)
-    libyaml = libyaml_wrap.dependency('yaml')
-endif
-
 control_sources = []
 
 controls_mode_files = {