Do you really need GitHub that much? How about a solution to host and share your version-controlled code with tools almost completely from OpenBSD base?
|Review head in browser?||Yes (cvsweb)||Yes|
|Public option to check out source code?||anoncvs||git clone|
|Submit firstname.lastname@example.org||Pull Requests|
|Private Repositories||Easy (leave out anoncvs) & free||Paid|
|Export to the other SCM system?||Yes (cvs2gitdump)||None known (git->cvs)|
|Need to create account to contribute?||No (check out with anoncvs, submit diff by email)||Yes|
|Written in||C & shell script; Perl (cvsweb)||git: C, Shell, Perl, Tcl, Python. GitHub: Ruby, Erlang|
|Creates and maintains bloated software?||Up to you||Yes: Electron, Atom|
|Graphical statistics on repos||e.g. cvsplot||In browser interface|
|Issue tracking||e.g. GNATS||In browser interface|
See also here for more arguments for cvs.
Status of opencvs