In a makefile, how to get the relative path from one absolute path to another?

Question

An example to illustrate my question:

Top level makefile

rootdir = $(realpath .)
export includedir = $(rootdir)/include
default:
    @$(MAKE) --directory         


        

Answer 1

Python is portable! So, I would suggest you this simple example in your submakefile

With current_dir and destination_dir paths os.path.relpath() does the job for you so you do not have to re-invent the wheel.

submakefile.mk

current_dir=$(CURDIR)
makefile_target:
    (echo "import os"; echo "print(os.path.relpath('$(destination_dir)', '$(current_dir)'))" )| python