Hubertus van Dam authored Aug 28, 2018 and Brad King committed Aug 30, 2018

All non-Intel BLAS library detection blocks have an if-statement
"if (NOT BLAS_LIBRARIES)" to ensure that if a BLAS library was
found we are not going to try and find another one. This causes
a problem when we have already found that we do not need to specify
a BLAS library, as the Intel MKL library takes precedence over
everything. Introducing the "if (NOT BLAS_LIBRARIES)" if-statement
fixes this problem.