Change _ssize() so it doesn't rely on sizeof(char) or sizeof(short):
8 bits is 1 byte, and that isn't about to change any time soon.  (I hope!)
diff --git a/Modules/ossaudiodev.c b/Modules/ossaudiodev.c
index 7b9feae..5df1d1a 100644
--- a/Modules/ossaudiodev.c
+++ b/Modules/ossaudiodev.c
@@ -554,13 +554,13 @@
     case AFMT_A_LAW:
     case AFMT_U8:
     case AFMT_S8:
-        *ssize = sizeof(char);
+        *ssize = 1;                     /* 8 bit formats: 1 byte */
         break;
     case AFMT_S16_LE:
     case AFMT_S16_BE:
     case AFMT_U16_LE:
     case AFMT_U16_BE:
-        *ssize = sizeof(short);
+        *ssize = 2;                     /* 16 bit formats: 1 byte */
         break;
     case AFMT_MPEG:
     case AFMT_IMA_ADPCM: