[Boost-build] rubbish parallel builds with mingw64

Subject: [Boost-build] rubbish parallel builds with mingw64
From: John Maddock (jz.maddock_at_[hidden])
Date: 2015-06-25 06:31:10

Folks,

I've noticed something very strange, and very annoying with mingw builds 
- the link steps all seem to be performed serially, never in parallel - 
is this a known issue?

I'm using a win64 build of bjam, plus ming-x64.  Building with msvc with 
the same bjam executable works fine, as does building on Linux with GCC.

Even if I kill the build and restart, it still runs all the remaining 
link steps in series, and it takes an age with mingw.

Any ideas?

Thanks, John.