There are several file system features that are not currently supported by NuttX. ftruncate/truncate is one that is noted in the TODO list:
utimes() is another. Currently only FAT supports file times and there is no file system interface to change file times. http://pubs.opengroup.org/onlinepubs/009695399/functions/utimes.html
You can see the current file system interface in the file include/nuttx/fs/fs.h, struct mountpt_operations. Any new file system operations would need to add methods to that structure (and implement them in all existing file systems... that is the hard part).
I suspect that you could just stub out utimes(). But fruncate() is a problem. ftruncate can be used to either make a file smaller or larger. Larger is not a problem; I think you can do that with lseek (http://pubs.opengroup.org/onlinepubs/009695399/functions/lseek.html) or just by extending the file with zero data (I have never tried lseek for that purpose, however.). But I don't know if any way to make a file smaller without ftruncate.
I assume that SQLite really just wants to create a fixed size file form random access. If that is the case, there are other ways around that.