"true" is valid for all Msvc versions:
see: Microsoft.Link.Common.props, lines 51, 52
<GenerateDebugInformation Condition="'$(UseDebugLibraries)' == 'true' and '%(Link.GenerateDebugInformation)'==''">DebugFastLink</GenerateDebugInformation>
<GenerateDebugInformation Condition="'$(UseDebugLibraries)' != 'true' and '%(Link.GenerateDebugInformation)'==''">Debug</GenerateDebugInformation>