Broken master and newcomers.

Hi.

I experience quite frequently that new contributors follow the instructions, but end up with a 
master that will not compile, leaving a frustrated contributors, and causing us to use time here on 
the list (or my private mailbox).

I have been thinking for a while, if we could get jenkins to keep a marker of the last buildable 
version, store it somwhere easy to grap (preferable in the repo itself), and then extend our build 
instructions to do "git checkout" to that point.

An alternative (which I have seen used in another project), would be to let jenkins generate a 
source tar ball, incl. the .git directory, of the latest sane build.

I know many will say, but master is sometimes broken, you have to live with that. That is a 
statement I agree with, for anything else than the first build.

Any thought on how we can secure new contributors get a buildable version the first time ?

thanks in advance for any input.
rgds
jan i.