Please support cmake-4.0 with lib64 libdir on Fedora

[yarda]

Fedora 43 (rawhide) introduced cmake-4.0, which dropped -DLIB_SUFFIX [1]. This causes that now on Fedora 64 bit the libraries are installed into /usr/lib instead of the /usr/lib64. GNURadio switched to the GNUInstallDirs [2]. I think something similar will be required here, because now I had to build it with the following workaround in the Fedora downstream:

%cmake \
%if "%{?_lib}"=="lib64"
  -DLIB_SUFFIX=64
%endif

[1] https://bugzilla.redhat.com/show_bug.cgi?id=2351130
[2] https://patch-diff.githubusercontent.com/raw/gnuradio/gnuradio/pull/7768.patch