enable MSVC warning w4661
enable MSVC warning w4661

As discovered in #5225, these warnings are useful.

sairajat/dealii,sairajat/dealii,naliboff/dealii,sairajat/dealii,naliboff/dealii,sairajat/dealii,sairajat/dealii,naliboff/dealii,sairajat/dealii,naliboff/dealii,naliboff/dealii,naliboff/dealii,naliboff/dealii,sairajat/dealii