Today I tried to build Go 1.4.1 from source but it failed with this error:

    go/src/liblink/anames9.c:6:29: fatal error: ../cmd/9l/9.out.h: No such file or directory

At first I thought the building routine might have be changed so I opened and read Installing Go from Source again, carefully, and found nothing special.

Then I searched for the error source and it turned out that I should deleted anames*.c, manually. There is no document and no automatic cleaning script, and you would have to figure it out yourself if no one ever mentioned it (source).