This commit[1] made a lot of changes to digestauth.c, including using a bunch of VLAs, which are not supported in all compilers, one of which is Visual Studio.
If you want to keep supporting Visual Studio, those will have to be arrays of constant size, or allocated on the heap. [1] https://gnunet.org/git/libmicrohttpd.git/commit/src/microhttpd/digestauth.c?id=bcba3f58c5fc9b4a3776494d3edddceb244ab110 -- Jonathan McDougall
