the bash scripts and makefiles for building go didn't take into account
the fact $GOROOT / $GOBIN could both be directories containing whitespaces,
and was not possible to build it in such a situation.
this commit adjusts the various makefiles/scripts to make it aware of that
possibility, and now it builds successfully when using a path with whitespaces
as well.
Fixes#115.
R=rsc, dsymonds1
https://golang.org/cl/157067
Meant as illustration of the Go pattern that is using
goroutines and channels to handle exceptional situations.
Note: There is no need for "Finally" since the
"try block" (the function f supplied to Try)
cannot do a Smalltalk-style non-local return
and terminate the function surrounding Try.
Replaces CL 157083.
R=r, rsc
https://golang.org/cl/157087
