Don't break build if src folder is not present (#701).

Author: Cesar Blum Silveira

makefile.shade

@@ -7,9 +7,9 @@ use-standard-lifecycle
 k-standard-goals
 custom-goals
 
-exec program='dotnet' commandline='restore ../../tools/Microsoft.AspNetCore.Server.Kestrel.GeneratedCode' workingdir='${kestrelSrcDir}'
-exec program='dotnet' commandline='run -p ../../tools/Microsoft.AspNetCore.Server.Kestrel.GeneratedCode Http/FrameHeaders.Generated.cs Http/Frame.Generated.cs' workingdir='${kestrelSrcDir}'
-
-exec program='dotnet' commandline='restore' workingdir='${kestrelSrcDir}'
-exec program='dotnet' commandline='restore ../../tools/Microsoft.AspNetCore.Server.Kestrel.LibuvCopier' workingdir='${kestrelSrcDir}'
-exec program='dotnet' commandline='run -p ../../tools/Microsoft.AspNetCore.Server.Kestrel.LibuvCopier' workingdir='${kestrelSrcDir}'
+#initialize if='Directory.Exists("src")'
+  exec program='dotnet' commandline='restore ../../tools/Microsoft.AspNetCore.Server.Kestrel.GeneratedCode' workingdir='${kestrelSrcDir}'
+  exec program='dotnet' commandline='run -p ../../tools/Microsoft.AspNetCore.Server.Kestrel.GeneratedCode Http/FrameHeaders.Generated.cs Http/Frame.Generated.cs' workingdir='${kestrelSrcDir}'
+  exec program='dotnet' commandline='restore' workingdir='${kestrelSrcDir}'
+  exec program='dotnet' commandline='restore ../../tools/Microsoft.AspNetCore.Server.Kestrel.LibuvCopier' workingdir='${kestrelSrcDir}'
+  exec program='dotnet' commandline='run -p ../../tools/Microsoft.AspNetCore.Server.Kestrel.LibuvCopier' workingdir='${kestrelSrcDir}'