Apply workaround for __has_include(<...>) and ICCAVR. (#593)
ICCAVR: IAR C/C++ Compiler V6.70.1.929 for Atmel AVR
There seems to be an issue with the ICCAVR compiler and `__has_include(<...>)` syntax:
```
Error[Pe008]: missing closing quote etl\include\etl\placement_new.h 48
Tool Internal Error:
Internal Error: [Front end]: assertion failed at: "..\..\Translator\compiler_core\src\parser\edg\literals.c", line 1159
Internal Error: [Front end]: assertion failed at: "..\..\Translator\compiler_core\src\parser\edg\literals.c", line 1159 etl\include\etl\placement_new.h 48
Error while running C/C++ Compiler
```
Which is weird, as I wonder why `__has_include` is defined in first place. The compiler is supposed to support some dialect of C++98.
Anyhow, `__has_include()` seems to work in general with ICCAVR. And with this change the code compiles well.
