If you are interested to use Intel's C/C++ compiler instead of the GCC, you have to guarantee with the compiler flag -ffreestanding that the compiler doesn't use the standard environment of your host system. Instead of using the standard path, you have to set with the compiler flag -I the include path to HermitCore's environment. However, Intel's compiler creates per default object files for the host system. Our toolchain includes the program x86_64-hermit-elfedit that is able to convert with the flag --output-osabi HermitCore these files to HermitCore's object files. For linking all object files to a HermitCore executable, you have to use the linker of our toolchain because it includes a valid linker script, which is required to build a bootable executable.
To summarize this guideline, you find below an abstract of a Makefile, which creates a HermitCore executable for the stream benchmark.
ELFEDIT_FOR_TARGET = x86_64-hermit-elfedit
CC_FOR_TARGET = x86_64-hermit-gcc
CC = icc
CFLAGS = -m64 -O3 -xHost -I$(TOPDIR)/hermit/usr/x86/x86_64-hermit/include/ -openmp -ffreestanding
STRIP_DEBUG = --strip-debug
KEEP_DEBUG = --only-keep-debug
default: stream
stream.o: stream.c
$(CC) -c $(CFLAGS) -o $@ $<
$(ELFEDIT_FOR_TARGET) --output-osabi HermitCore $@
stream: stream.o
$(CC_FOR_TARGET) -fopenmp -o $@ $<
$(OBJCOPY_FOR_TARGET) $(KEEP_DEBUG) $@ $@.sym
$(OBJCOPY_FOR_TARGET) $(STRIP_DEBUG) $@