git clone --recursive https://...

[Dr Rainer Woitok]

Greetings,

to build another project I need Boost version 1.60 or better.   However,
Ubuntu 16.04 (which I'm still using)  only provides Boost 1.58.   In the
past I solved similar problems by simply running

   git clone -n https://... xxx && hg convert -s git -d hg xxx yyy

and by then compiling the required version  of a dependency myself.  But
the Boost source repository contains what Git dubs "submodules" and thus
requires the "--recursive" option for "git clone".   Are these submodul-
es the Git aequivalent of  Mercurial's sub-repositories?   But more imp-
ortantly:  is Mercurial's "convert" extension  or the "hg-git" extension
capable of automatically converting  all these submodules  to Mercurial?
Or do I have to write a shell script  which later pulls  any new change-
sets for all these submodules  and then incrementally "hg convert"s them
to Mercurial?

Any information or pointers welcome.

Sincerely,
  Rainer