It looks like it was copy-pasted, so in case anyone wonders what some of
those methods do without looking at them, and for the sake of
completeness, fix them.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

Rename the VIR_MOCK_IMPL* macros to VIR_MOCK_WRAP*
and add new VIR_MOCK_IMPL macros which let you directly
implement overrides in the preloaded source.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>
Signed-off-by: NJim Fehlig <jfehlig@suse.com>

dlfcn.h does not exist on Win32 so must only be used
conditionally
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>

Introduce virmock.h which provides some macros to assist in
creation of LD_PRELOAD overrides. When these are used, the
LD_PRELOAD code simply has some stubs which forward to a
wrapper function inside the main test case. This means that
logic for the test no longer has to be split between the
virXXXtest.c and virXXXmock.c files. It will also make it
possible to provide some common reusable modules for mocking
code like DBus.
Signed-off-by: NDaniel P. Berrange <berrange@redhat.com>