Fix: "invalid conversion from ‘int" when compiling version 1.0.5 (mic…

[DGdev91]

Had issue compiling on ArchLinux, i currently have microhttpd 0.9.71. Seems like i'm not the only one, there's an open issue complaining for the same problem #2685

Using the MHD_Result enum instead of "int" solved the problem (still had to make a static cast for MHD_digest_auth_check, which returns an int)

[superzerg]

thanks for the fix, I had the same problem on Debian 10 and it worked like a charm !