Add a SONAME to shared libraries

Ginkgo is written in C++ and does not guarantee any stable ABI.
Consequently, all shared libraries should be annotated by an appropriate
SONAME (this patch simply uses the release version). This ensures
conformity with best practices and library requirements for popular
Linux distributions (e.g., Debian/Ubuntu). It also prevents silent
breakage (at dynamic link time / run time) when the library ABI changed
and user code should have been recompiled.

cmake/build_helpers.cmake

@@ -17,6 +17,9 @@ function(ginkgo_compile_features name)
  if(GINKGO_WITH_IWYU AND GINKGO_IWYU_PATH)
  set_property(TARGET "${name}" PROPERTY CXX_INCLUDE_WHAT_YOU_USE ${GINKGO_IWYU_PATH})
  endif()
+ # Set an appropriate SONAME
+ set_property(TARGET "${name}" PROPERTY
+ SOVERSION "${Ginkgo_VERSION}")
  if(GINKGO_CHANGED_SHARED_LIBRARY)
  # Put all shared libraries and corresponding imported libraries into the specified path
  set_property(TARGET "${name}" PROPERTY