For some reason, mjpegtools gives the following error when compiling it with macports in OS X Lion:
mjpegtools wouldn't compile (mjpegtools-2.0.0: error: use of undeclared identifier DeleteRegion).
This problem has been identified as being due to the clint compiler. The simple solution was
sudo port clean mjpegtools sudo port -sv install mjpegtools configure.compiler=llvm-gcc-4.2
Tim Saucer 