meson: only require cpp for tests

Signed-off-by: James Hilliard <james.hilliard1@gmail.com>

meson.build

@@ -1,5 +1,5 @@
 project(
-	'wayland', 'c', 'cpp',
+	'wayland', 'c',
 	version: '1.19.90',
 	license: 'MIT',
 	meson_version: '>= 0.52.1',

tests/meson.build

@@ -64,15 +64,17 @@ executable(
 	dependencies: test_runner_dep
 )
 
-test(
-	'cpp-compile-test',
-	executable(
+if add_languages('cpp')
+	test(
 		'cpp-compile-test',
-		'cpp-compile-test.cpp',
-		wayland_server_protocol_h,
-		include_directories: src_inc
+		executable(
+			'cpp-compile-test',
+			'cpp-compile-test.cpp',
+			wayland_server_protocol_h,
+			include_directories: src_inc
+		)
 	)
-)
+endif
 
 sed_path = find_program('sed').path()