Hi,
Since Intel developers announced "C11 Support in Intel C++ Compiler" (https://software.intel.com/en-us/articles/c11-support-in-intel-c-compiler), for some reason it was not added to "C/C++ => Language [Intel C++]" menu of Visual Studio project properties (same for C++14, BTW).
Сould you open a ticket for IPSXE 2016 to remove parameters "Enable C99 support" and "Enable C++11 Support" from menu "Language [Intel C++]" and add parameter "Language Support" with options: (/Qstd=c99), (/Qstd=c11), (/Qstd=c++11), (/Qstd=c++14)?
Regards,
Alexander