patch 8.1.1502: cannot play any sound

Problem:    Cannot play any sound.
Solution:   Use libcanberra if available.  Add sound functions.
diff --git a/src/evalfunc.c b/src/evalfunc.c
index bc60567..4297379 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -925,6 +925,12 @@
     {"sinh",		1, 1, f_sinh},
 #endif
     {"sort",		1, 3, f_sort},
+#ifdef FEAT_SOUND
+    {"sound_playevent",	1, 2, f_sound_playevent},
+    {"sound_playfile",	1, 2, f_sound_playfile},
+    {"sound_stop",	1, 1, f_sound_stop},
+    {"sound_stopall",	0, 0, f_sound_stopall},
+#endif
     {"soundfold",	1, 1, f_soundfold},
     {"spellbadword",	0, 1, f_spellbadword},
     {"spellsuggest",	1, 3, f_spellsuggest},
@@ -6782,6 +6788,9 @@
 #ifdef FEAT_NETBEANS_INTG
 	"netbeans_intg",
 #endif
+#ifdef FEAT_SOUND
+	"sound",
+#endif
 #ifdef FEAT_SPELL
 	"spell",
 #endif