include - Adding a directory for the headers in a Makefile

Question

Hello I would like to ask you, If someone knows how can I add a directory for the header files in the Makefile to avoid the error *.h not found, I have tried this option but does not work:

INC_PATH := -I /directory/to/add

Answer 1

At least for GNU make, try the implicit variable CFLAGS, as in:

CFLAGS=-I/directory/to/add