Ocamlbuild & Coq
----------------

A quick note in case someone else gets interested someday in compiling
Coq via ocamlbuild : such an experimental build system has existed
in the past (more or less maintained from 2009 to 2013), in addition
to the official build system via gnu make. But this build via
ocamlbuild has been severly broken since early 2014 (and don't work
in 8.5, for instance). This experiment has attracted very limited
interest from other developers over the years, and has been quite
cumbersome to maintain, so it is now officially discontinued.
If you want to have a look at the files of this build system
(especially myocamlbuild.ml), you can fetch :
 - my last effort at repairing this build system (up to coqtop.native) :
   https://github.com/letouzey/coq-wip/tree/ocamlbuild-partial-repair
 - coq official v8.5 branch (recent but broken)
 - coq v8.4 branch(less up-to-date, but works).

For the record, the three main drawbacks of this experiments were:
 - recurrent issues with circularities reported by ocamlbuild
   (even though make was happy) during the evolution of Coq sources
 - no proper support of parallel build
 - quite slow re-traversal of already built things
See the two corresponding bug reports on Mantis, or
https://github.com/ocaml/ocamlbuild/issues/52

As an interesting feature, I successfully used this to cross-compile
Coq 8.4 from linux to win32 via mingw.

Pierre Letouzey, june 2016
