$ make -j12                     
mcs -target:library -out:"./Server.dll" -r:"./Settings.dll",System.Drawing.dll,System.Web.dll,System.Data.dll,System.IO.Compression.FileSystem.dll -nowarn:0618,0219,0414,1635 -d:MONO -d:ServUO -d:ServUO58 -d:NEWTIMERS -d:NEWPARENT -nologo -optimize -unsafe -recurse:"./Server/*.cs"
rm -f ServUO.sh
rm -f ServUO.exe
rm -f ServUO.exe.mdb
rm -f *.bin
./Server/ClientVersion.cs(19,39): error CS1644: Feature `readonly structs' cannot be used because it is not part of the C# 7.0 language specification
./Server/NativeReader.cs(135,25): warning CS1692: Invalid number
./Server/NativeReader.cs(147,25): warning CS1692: Invalid number
./Server/Network/Encryption/LoginKeys.cs(8,35): error CS1644: Feature `readonly structs' cannot be used because it is not part of the C# 7.0 language specification
Compilation failed: 2 error(s), 2 warnings
make: *** [Makefile:38: Server.dll] Erro 1