meson: Define python3 and python3-yaml required dependencies

With this change, meson will complain specifically about missing
python3 and missing python3-yaml. As specified by meson
documentation: https://mesonbuild.com/Python-module.html,
this change requires meson v0.51.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

meson.build

@@ -101,6 +101,9 @@ add_project_link_arguments(cpp_arguments, language : 'cpp')
 
 libcamera_includes = include_directories('include')
 
+# Sub-directories fill py_modules with their dependencies.
+py_modules = []
+
 # Utilities are parsed first to provide support for other components.
 subdir('utils')
 
@@ -143,5 +146,9 @@ pkg_mod.generate(libraries : libcamera,
                  description : 'Complex Camera Support Library',
                  subdirs : 'libcamera')
 
+# Check for python installation and modules.
+py_mod = import('python')
+py_mod.find_installation('python3', modules: py_modules)
+
 ## Summarise Configurations
 message('Enabled pipelines: ' + ', '.join(get_option('pipelines')))

utils/meson.build

@@ -3,6 +3,7 @@
 subdir('ipu3')
 
 ## Code generation
+py_modules += ['yaml']
 gen_controls = files('gen-controls.py')
 gen_formats = files('gen-formats.py')
 gen_header = files('gen-header.sh')