Currently, building BIND using "--without-dlopen" universally breaks
building unit tests which employ the --wrap linker option (because the
replacement functions are put in a shared library and building shared
objects requires "--with-dlopen"). Fix by moving the overridden symbol,
isc_nmhandle_unref(), to lib/ns/tests/nstest.c and dropping
lib/ns/tests/wrap.c altogether. This makes lib/ns/tests/Makefile.in
simpler and prevents --without-dlopen from messing with the process of
building unit tests.
Remove parts of configure.ac which are made redundant by the above
changes.
Put the replacement definition of isc_nmhandle_unref() inside an #ifdef
block, so that the build does not break for non-libtool builds (see
below).
These changes allow the broadest possible set of build variants to work
while also simplifying the build process:
- for libtool builds, overriding isc_nmhandle_unref() is done by
placing that symbol directly in lib/ns/tests/nstest.c and relying on
the dynamic linker to perform symbol resolution in the expected way
when the test binary is run,
- for non-libtool builds, overriding isc_nmhandle_unref() is done
using the --wrap linker option (the libtool approach cannot be used
in this case as multiple strong symbols with the same name cannot
coexist in the same binary),
- the "--without-dlopen" option no longer affects building unit tests.