Adding a shared library version without explicit soname for easier loading.

[annakawecka]

Error was: could not find lib/libiss_sort.so, when trying to use libiss_sort.so from a program compiled in another directory. The explicit setting of so name in the library prevented the library to be found at program load time.
Trying to remove the trailing /lib in -L options etc was not successful with the explicit soname including lib/.

[lpgaff]

Ah, this is interesting. We observed this problem recently and didn't know the problem, because it seems to be system dependent. Should we not just use the second version in the Makefile, i.e. no need to keep the original (broken) library?

[annakawecka]

Whatever works for you. I just didn't want to mess with the original library

[inkdot7]

After a bit more digging around, it turns out that a slash (/) in soname make the dynamic linker treat it as a path and not do any search for the library at all.

Suggest to use #138 and #139 instead, in order to keep the other options that $(SHAREDSWITCH) bring in for MacOS.

[lpgaff]

overtaken by changes in #139