darshan-util implicitly relies on bzip2 binary

When building Darshan in a docker image (centos:7), it looks like the absence of the bzip2 binary isn't correctly handled.

The absence of bzlib.h is detected:

[root@2883456d11ec darshan-util]# ./configure
...
checking if bzlib is wanted... yes
checking for BZ2_bzCompressInit in -lbz2... no
checking bzlib.h usability... no
checking bzlib.h presence... no
checking for bzlib.h... no
checking bzlib in /usr... failed
configure: WARNING: libbz2 not found; Darshan utilities will use gzip only.

But then

[root@2883456d11ec darshan-util]# make
tar xjvf ./extern/uthash-1.9.2.tar.bz2
tar (child): bzip2: Cannot exec: No such file or directory
tar (child): Error is not recoverable: exiting now
tar: Child returned status 2
tar: Error is not recoverable: exiting now
make: *** [uthash-1.9.2] Error 2