Error trying to build dlang.org

[Tony]

Following the instructions here on Ubuntu 16.04:

https://github.com/dlang/dlang.org/blob/master/CONTRIBUTING.md

I did the command

make -f posix.mak html

but it failed to successfully complete:
-----------------------------------------------
make[1]: Leaving directory '/home/user/dlang/dmd/src'
../dmd/generated//release//dmd -c -o- 
-Df/home/user/dlang/dlang.org/web/spec/spec.html macros.ddoc 
html.ddoc dlang.org.ddoc doc.ddoc .generated/2.078.0.ddoc  
.generated/dblog_latest.ddoc .generated/twid_latest.ddoc 
spec/spec.ddoc spec/spec.dd
make: ../dmd/generated//release//dmd: Command not found
posix.mak:466: recipe for target 
'/home/user/dlang/dlang.org/web/spec/spec.html' failed
make: *** [/home/user/dlang/dlang.org/web/spec/spec.html] Error 
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