Revert "use sf_open_fd"

This reverts commit 6e66850d90.

examples/embed.scri

@@ -1,3 +1,3 @@
 load :0;
-embed 3 1 file.mp3
+embed 3 1 ./file.mp3
 quicksave;

src/image.zig

@@ -31,17 +31,14 @@ pub fn sopen(
     var cstr_path = try std.cstr.addNullByte(allocator, path);
     defer allocator.free(cstr_path);
 
-    var fs_file = try std.fs.File.openRead(path);
-
-    var file = c.sf_open_fd(fs_file.handle, mode, fmt, 1);
+    var file = c.sf_open(cstr_path.ptr, mode, fmt);
     const st: i32 = c.sf_error(file);
 
     if (st != 0) {
-        var msg = c.sf_error_number(st);
         std.debug.warn(
             "Failed to open {} ({})\n",
             path,
-            msg[0..std.mem.len(u8, msg)],
+            c.sf_error_number(st),
         );
 
         return ImageError.OpenFail;