-J directory
The -J option adds directory to the end of the list of directories to search for source files included by the #include preprocessor command for C files and the INCLUDE assembler directive. The directory $(InstallDir)/include is automatically added to the system include path before any directory added by the -J command line option.
For example, to tell the compiler to search the directories ../include and ../lib/include for included system files when compiling file.c and writing the output to file.hzo you could use the following:
hcc -J../include -J../lib/include file.c -o file.hzo file.c