Clean up C++ test configuration and documentation

2 files changed, 7 insertions, 5 deletions

diff --git a/INSTALL.md b/INSTALL.md
index 903e680..ea54053 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -29,6 +29,12 @@ configuration:
   * `CFLAGS`: C compiler options.
   * `LDFLAGS`: Linker options.
 
+Some optional tests also use the C++ compiler from the environment (unless the
+`tests_cpp` option is disabled):
+
+  * `CXX`: Path to C++ compiler.
+  * `CXXFLAGS`: C++ compiler options.
+
 However, it is better to use meson options for configuration.  All options can
 be inspected with the `configure` command from within the build directory:
 
diff --git a/test/meson.build b/test/meson.build
index 6691f46..72d723b 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -159,11 +159,7 @@ if cc.get_id() != 'emscripten'
   )
 endif
 
-if not get_option('tests_cpp').disabled() and add_languages(
-  ['cpp'],
-  native: false,
-  required: get_option('tests_cpp').enabled(),
-)
+if add_languages(['cpp'], native: false, required: get_option('tests_cpp'))
   cpp = meson.get_compiler('cpp')
 
   cpp_test_args = []