Rolf Eike Beer authored Apr 24, 2018 and Brad King committed Apr 24, 2018

Since commit v3.11.0-rc1~177^2 (FindBLAS: optionally query pkg-config
for a library, 2017-12-15) the `BLAS_LIBRARIES` result variable may
incorrectly contain the name of an imported target.  Instead store the
list of libraries in the variable.  Unfortunately pkg_check_modules does
not provide a way to get this so we need to use a (temporary) hack of
reading `INTERFACE_LINK_LIBRARIES` from the interface library target.

Fixes: #17934