MP3Decoder: ssize_t type is not portable, don't use it

Author: jepler

shared-module/audiomp3/MP3Decoder.c

@@ -48,7 +48,7 @@ static bool stream_readable(void *stream) {
 
 // (near copy of mp_stream_posix_read, but with changes)
 // (circuitpy doesn't enable posix stream routines anyway)
-static ssize_t stream_read(void *stream, void *buf, size_t len) {
+static mp_int_t stream_read(void *stream, void *buf, size_t len) {
     int errcode;
     mp_obj_base_t *o = MP_OBJ_TO_PTR(stream);
     const mp_stream_p_t *stream_p = MP_OBJ_TYPE_GET_SLOT(o->type, protocol);

shared-module/audiomp3/MP3Decoder.h

@@ -15,9 +15,9 @@
 
 typedef struct {
     uint8_t *buf;
-    ssize_t size;
-    ssize_t read_off;
-    ssize_t write_off;
+    mp_int_t size;
+    mp_int_t read_off;
+    mp_int_t write_off;
 } mp3_input_buffer_t;
 
 typedef struct {