Always compile the `oss_sample_types` function
Bug: https://bugs.gentoo.org/show_bug.cgi?id=621758

--- a/audio.c
+++ b/audio.c
@@ -743,7 +743,6 @@
 }
 
 
-#if (!HAVE_ALSA)
 static int oss_sample_types(int ur_dev, mus_sample_t *val)
 {
   int fd, samp_types = 0, sys, ind;
@@ -774,7 +773,6 @@
   val[0] = (mus_sample_t)(ind - 1);
   return(MUS_NO_ERROR);
 }
-#endif