meson: build docs by default, but allow disabling it

This is the behavior of configure as well.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>

meson.build

@@ -222,9 +222,8 @@ pkgconfig.generate(
 
 ############ documentation ############
 
-doxygen = find_program('doxygen',
-		       required : false)
-if doxygen.found()
+if get_option('documentation')
+	doxygen = find_program('doxygen')
 	doxygen_version_cmd = run_command(doxygen.path(), '--version')
 	if doxygen_version_cmd.returncode() != 0
 		error('Command "doxygen --version" failed.')

meson_options.txt

@@ -14,3 +14,7 @@ option('tests',
        type: 'boolean',
        default: true,
        description: 'Build the tests [default=true]')
+option('documentation',
+       type: 'boolean',
+       default: true,
+       description: 'Build the documentation [default=true]')