scons test fails for Visual Studio 2019

[ischoegl]

Cantera version

2.5.0a3

Operating System

Windows 10 / Visual Studio 2019

Python/MATLAB version

Anaconda 3.7

Expected Behavior

scons test runs without error

Actual Behavior

scons test fails with error C2512:, i.e.

test\general\test_units.cpp(8): error C2512: 'Cantera::UnitSystem': no appropriate default constructor available
C:\Users\<username>\Github\cantera\include\cantera/base/Units.h(100): note: see declaration of 'Cantera::UnitSystem'
test\general\test_units.cpp(17): error C2512: 'Cantera::UnitSystem': no appropriate default constructor available
C:\Users\<username>\Github\cantera\include\cantera/base/Units.h(100): note: see declaration of 'Cantera::UnitSystem'
test\general\test_units.cpp(27): error C2512: 'Cantera::UnitSystem': no appropriate default constructor available
C:\Users\<username>\Github\cantera\include\cantera/base/Units.h(100): note: see declaration of 'Cantera::UnitSystem'
test\general\test_units.cpp(36): error C2512: 'Cantera::UnitSystem': no appropriate default constructor available
C:\Users\<username>\Github\cantera\include\cantera/base/Units.h(100): note: see declaration of 'Cantera::UnitSystem'
test\general\test_units.cpp(66): error C2512: 'Cantera::UnitSystem': no appropriate default constructor available
C:\Users\<username>\Github\cantera\include\cantera/base/Units.h(100): note: see declaration of 'Cantera::UnitSystem'
test\general\test_units.cpp(79): error C2512: 'Cantera::UnitSystem': no appropriate default constructor available
C:\Users\<username>\Github\cantera\include\cantera/base/Units.h(100): note: see declaration of 'Cantera::UnitSystem'
test\general\test_units.cpp(88): error C2512: 'Cantera::UnitSystem': no appropriate default constructor available
C:\Users\<username>\Github\cantera\include\cantera/base/Units.h(100): note: see declaration of 'Cantera::UnitSystem'
test\general\test_units.cpp(96): error C2512: 'Cantera::UnitSystem': no appropriate default constructor available
C:\Users\<username>\Github\cantera\include\cantera/base/Units.h(100): note: see declaration of 'Cantera::UnitSystem'
test\general\test_units.cpp(112): error C2512: 'Cantera::UnitSystem': no appropriate default constructor available
C:\Users\<username>\Github\cantera\include\cantera/base/Units.h(100): note: see declaration of 'Cantera::UnitSystem'
test\general\test_units.cpp(119): error C2512: 'Cantera::UnitSystem': no appropriate default constructor available
C:\Users\<username>\Github\cantera\include\cantera/base/Units.h(100): note: see declaration of 'Cantera::UnitSystem'
test\general\test_units.cpp(129): error C2512: 'Cantera::UnitSystem': no appropriate default constructor available
C:\Users\<username>\Github\cantera\include\cantera/base/Units.h(100): note: see declaration of 'Cantera::UnitSystem'
scons: building terminated because of errors.

Steps to reproduce

1. Compile current master (commit 674c37c) using VS2019 (via MSVC 14.1)
2. Run scons test, which fails (see attached ... scons_test.log)
3. Details on the toolchain are posted here