package/clamav: needs dynamic library

package/clamav: needs dynamic library

Upstream commit
https://github.com/Cisco-Talos/clamav-devel/commit/9e20cdf6eaf545a66f55ce5ba85ef9a98dad3648
added dlopen() to others.c
https://github.com/Cisco-Talos/clamav-devel/blob/dev/0.104/libclamav/others.c#L199

"libclamav used to build in multiple stages where an earlier stage is
a static library containing utils required by the "shared" code.
Linking clamdscan and clamdtop with this libclamav utils static lib
allowed these two apps to function without libclamav. While this is
nice in theory, the practical gains are minimal and it complicates
the build system. As such, the autotools and CMake tooling was
simplified for improved maintainability and this feature was thrown
out. clamdtop and clamdscan now require libclamav to function."

Fixes:
http://autobuild.buildroot.net/results/e27/e276894781e3e37fbc03a0745738c61541e0a211/
http://autobuild.buildroot.net/results/552/552ee8d9e44152c9d7e315a5491542771264d466/
http://autobuild.buildroot.net/results/fde/fde4af47542f0eb0bd57b172c99bd086eb566b76/

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>