A friend of mine was trying to install go1.2 on his Ubuntu machine, and the compiler complained about a unistd.h file not being found. The problem was solved by installing build-essential.
Hence, why I propose that we add build-essential as a Linux requirement. I'm certain a lot of people will be spared the trouble of trying to figure out where the error is coming from.
Added build-essential to the Linux requirements
Without this instruction change, people might come across a "`unistd.h` not found" error.
I met some problem and It was solved by installing build-essential too.