Even though the gcc build runs fine, I'd like to know how to build with MSVC.
I have both the Platform Toolsets from:
- VS2015 | MSVC 14.0 | _MSC_VER == 1900
- VS2017 | MSVC 14.1 | _MSC_VER == 1910

Looking at C:\OpenModelica\share\omc\scripts\Compile.bat, it seems that VS2015 should be supported.
So
- I set up the environment in order to build with MSVC
- I compiled with omc with --target=msvc15 (that is quite misleading because it should be VS2015 or MSVC140, never mind...)
- I tried both with +simCodeTarget=Cpp and +simCodeTarget=C
- I compiled with nmake

and here are the results:
i) with +simCodeTarget=Cpp I get

fatal error C1853: 'C:/OpenModelica//include/omc/cpp/Core/Modelica.pch' precompiled header file is from a previous version of the compiler, or the precompiled header is C++ and you are using it from C (or vice versa)

ii) with +simCodeTarget=C I get a long list of

error C2732: linkage specification contradicts earlier specification

that, by the way occur in the declaration of extern "c" functions

iii) with +simCodeTarget=C and forcing to not use the precompiled header (putting a PCH_FILE=<nothing> in the makefile)I get

Severity    Code    Description    Project    File    Line    Suppression State

Error LNK2038 mismatch detected for '_MSC_VER': value '1900' doesn't match value '1800' in simulation.lib(simulation_runtime.cpp.obj)

so it seems that the simulation.lib library has been compiled with a _MSC_VER == 1800 i.e. VS2013 i.e. MSVC12.0 so it is not usable with other MSVC versions.

Is there any solution?
Does anyone successfully tried to build with MSVC?