Usually the compiler and assembler search for include files in the standard include directory created when the product is installed. If for some reason you wish to exclude these system locations from being searched when compiling a file, the -I- option will do this for you.
Preprocessor Options > Ignore Includes
The -I- option will clear any include directories previously set with the -I- option, so you must ensure that -I- comes before setting any directories you wish to search. Therefore, the following command line has a different effect to the command line above:
hcl -I../include -I../lib/include -I- file.c