The long-term used version of libjpeg, 6b, did not include the C++ guards in its include files. Thus the LO build fails with lots of jpegc.cxx:(.text+0xa44): undefined reference to 'jpeg_finish_compress(jpeg_compress_struct*)' because it's looking for C++-mangled symbols. It would be nice if LO included the extern C guards in all files that include jpeglib.h, as having double guards causes no harm. The files needed are jpegc.cxx and JpegReader.cxx.
Build problems to dev list, plz.