patch 8.1.1529: libcanberra is linked with even when not used

Problem:    Libcanberra is linked with even when not used.
Solution:   Have configure check for libcanberra only when wanted.
            (suggestions by Libor Bukata)
diff --git a/src/version.c b/src/version.c
index aa3986d..44ce639 100644
--- a/src/version.c
+++ b/src/version.c
@@ -778,6 +778,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1529,
+/**/
     1528,
 /**/
     1527,