The project cpputest\platforms\iar\CppUTest.eww fails to build with IAR 8.1:

CommandLineArguments.cpp  
Error[Pe135]: namespace "std" (declared at line 185 of "C:\Program Files (x86)\IAR Systems\Embedded Workbench 8.1\arm\inc\c\yvals.h") has no member "nullptr_t" cpputest\include\CppUTest\SimpleString.h 182 
Error while running C/C++ Compiler 

I have added cstddef as preinclude:

Preinclude file: 
C:\Program Files (x86)\IAR Systems\Embedded Workbench 8.1\arm\inc\cpp\cstddef

But then I have these errors:

Error[Pe079]: expected a type specifier cpputest\src\CppUTest\SimpleString.cpp 548 
Warning[Pe815]: type qualifier on return type is meaningless cpputest\src\CppUTest\SimpleString.cpp 548 
Error[Pe018]: expected a ")" cpputest\src\CppUTest\SimpleString.cpp 548 
Error while running C/C++ Compiler 

Which occur here:

#if __cplusplus > 199711L && !defined __arm__
SimpleString StringFrom(const std::nullptr_t __attribute__((unused)) value)
{
    return "(null)";
}

It seems neither __arm__ nor __cplusplus is defined. So I added them as defines. I also disabled the exceptions because the library is meant to be used on embedded devices.

CPPUTEST_STD_CPP_LIB_DISABLED=1
__arm__
__cplusplus=200000L

This time the project builds without errors