Assuming, you're using LibRaw's dcraw_emu sample, not some other app that uses LibRaw:
LibRaw's own TIFF writer routine is very simple, it is used to not depend on additional libraries (e.g. libtiff). So only minimal EXIF data is recorded into output.
LibRaw is opensource, we're open to user contribution. So feel free to implement own TIFF writer (w/ extensive EXIF recording) we will be happy to add it to LibRaw (if you wish so).
Assuming, you're using LibRaw's dcraw_emu sample, not some other app that uses LibRaw:
LibRaw's own TIFF writer routine is very simple, it is used to not depend on additional libraries (e.g. libtiff). So only minimal EXIF data is recorded into output.
LibRaw is opensource, we're open to user contribution. So feel free to implement own TIFF writer (w/ extensive EXIF recording) we will be happy to add it to LibRaw (if you wish so).