[Feature] Make NEW policy:CMP0091 behaviour respect DEBUG_CONFIGURATIONS property
In the description for Policy CMP0091, relating to runtime library linking in MSVC, it is stated that
MSVC_RUNTIME_LIBRARYtarget property may be set to select the MSVC runtime library. If they are not set then CMake uses the default value
MultiThreaded$<$<CONFIG:Debug>:Debug>DLLwhich is equivalent to the original flags.
From my understanding, this default value makes the assumption that there is one debug build target, and this is called Debug. Projects that make use of the DEBUG_CONFIGURATIONS property to define additional debug build targets (e.g. a DebugOptimised target) can easily get caught out by this and link against the wrong runtime. I would therefore like to propose for this policy to respect the value for DEBUG_CONFIGURATIONS when determining whether the Debug or Release runtime library should be linked, or if this is already the case in practice, for the documentation to reflect this.
Thank you in advance!