Looks like bzip2 could be a drop in.  Configure looks for a GZIP
environment
variable for the path to gzip in preference to a search.  Perhaps
define it
as "export GZIP=/usr/local/sbin/amzip" or wherever other amanda
executables
reside before doing the configure.

Then you could install gzip or bzip2 as "amzip" and test each one.

Base on the man pages on my Solaris system the options are similar.

They both take the the "-dc" option for decompression to stdout.
However, you may have to change some #define's in config.h.

/* Define to the exact path to the gzip or the compress program.  */
#undef COMPRESS_PATH

configure may find it from $GZIP

/* Define to the suffix for the COMPRESS_PATH compression program.  */
#undef COMPRESS_SUFFIX

".bz2" maybe??  But won't be the same for both bzip2 and gzip.

/* Define as the command line option for fast compression.  */
#undef COMPRESS_FAST_OPT
/* Define as the command line option for best compression.  */
#undef COMPRESS_BEST_OPT

Both take number options, -1 to -9, 
But amanda seems to use --fast (aka -1) and --best (aka -9).
Changing this to define them as -1 and -9 should work for both.

/* Define as the exact path to the gzip or compress command.  */
#undef UNCOMPRESS_PATH

Should be same as COMPRESS_PATH

/* Define as any optional arguments to get UNCOMPRESS_PATH to
uncompress.  */
#undef UNCOMPRESS_OPT                                                
                                     

Current seems to use -dc so no change should be needed.


For those who wish to try it, any reason this would not work?