meson: add simple test executable for libmpv

This can be used to make sure that the built libmpv is functional.

libmpv/test.c

@@ -0,0 +1,29 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * mpv is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <libmpv/client.h>
+
+int main(void)
+{
+    mpv_handle *handle = mpv_create();
+    if (!handle)
+        return 1;
+    if (mpv_initialize(handle))
+        return 1;
+    mpv_destroy(handle);
+    return 0;
+}

meson.build

@@ -1683,6 +1683,9 @@ if get_option('libmpv')
     headers = ['libmpv/client.h', 'libmpv/render.h',
                'libmpv/render_gl.h', 'libmpv/stream_cb.h']
     install_headers(headers, subdir: 'mpv')
+
+    libmpv_test = executable('libmpv-test', 'libmpv/test.c', link_with: [libmpv])
+    test('libmpv', libmpv_test)
 endif
 
 if get_option('cplayer')