Here is a patch to get StegDetect 0.6 to compile with GCC 4.x.

I took the Debian 0.6-6 patch and added the debug comment out line at the end of it.

To use the patch:

1) Untar the the stegdetect-0.6.tar.gz file
2) In the directory before stegdetect-0.6 do:
patch -p0 < stegdetect-0.6-6.diff

Download the patch: stegdetect_0.6-6.diff.gz