lx_hybrid_ctors: remove 'soname' link option

This patch removes the 'soname' link option for building the host
library for the 'lx_hybrid_ctors' test. Without this option, the
library's absolute path at build time gets hardcoded into the
application, which should be okay for this simple test case.

Fixes #638.
base: fix faults in rm_session de-constructor path

First make the clients inaccessible and dissolve them from the entrypoint. If
this isn't the first step the clients may be obtained again between
the unlock and lock steps in the destructor.

Additionally the clients may be removed in between the unlock and call
sequence, which renders such client pointers dangling and causes spurious page
faults. Keep instead a lock as long as possible and when it is required to
release a lock, then the pointer to the objects must be revalidated.

Replace the dissolve function with a remove_client implementation as suggested
by #13, which avoids that the cpu_session may call dissolve with a dangling
pointer of a already removed rm_client object. Instead the pager must be
released explicitly.

Related to issue #549
Related to issue #394
Related to issue #13
base: add remove_client to rm_session

Fixes #13