Hello - 
I've been building boost with a script* (via https://studiofreya.com/2017/04/23/building-boost-1-64-with-visual-studio-2017/).  My Visual C++ project is a static lib so link and runtime-link are static.
It's worked for several past build releases.  Now with build 1_66, not all x64 libraries are built.  There is 74 libraries in the win32 directory and only 27 in the x64.

I locate the script using "x64 Native Tools Command Propt for VS2017"

I am using Windows7.

Any advice is appreciated.

*@echo off
rem Directory to boost root
set boost_dir=boost_1_66_0

rem Number of cores to use when building boost

rem What toolset to use when building boost.

rem Visual Studio 2012 -> set msvcver=msvc-11.0
rem Visual Studio 2013 -> set msvcver=msvc-12.0
rem Visual Studio 2015 -> set msvcver=msvc-14.0
rem Visual Studio 2017 -> set msvcver=msvc-14.1

set msvcver=msvc-14.1

rem Start building boost
echo Building %boost_dir% with %cores% cores using toolset %msvcver%.

cd %boost_dir%
call bootstrap.bat

rem Static libraries
b2 -j%cores% toolset=%msvcver% address-model=64 architecture=x86 link=static threading=multi runtime-link=static --build-type=complete stage --stagedir=stage/x64 
b2 -j%cores% toolset=%msvcver% address-model=32 architecture=x86 link=static threading=multi runtime-link=static --build-type=complete stage --stagedir=stage/win32