cur_makefile := $(lastword $(MAKEFILE_LIST)) give me some examples to explain this assignment

Sure, here are a few examples to help explain this assignment:

Example 1:
Suppose you have a Makefile called "myproject/Makefile" in the following directory structure:

myproject/
├── src/
│   ├── file1.cpp
│   ├── file2.cpp
│   └── file3.cpp
├── include/
│   ├── header1.h
│   ├── header2.h
│   └── header3.h
└── Makefile

If you add the following line to your Makefile:

cur_makefile := $(lastword $(MAKEFILE_LIST))

Then the variable "cur_makefile" will be set to "myproject/Makefile".

Example 2:
Suppose you have a project with multiple Makefiles in different subdirectories, like this:

project/
├── Makefile
├── dir1/
│   ├── file1.cpp
│   ├── file2.cpp
│   └── Makefile
├── dir2/
│   ├── file3.cpp
│   ├── file4.cpp
│   └── Makefile
└── dir3/
    ├── file5.cpp
    ├── file6.cpp
    └── Makefile

If you add the following line to the Makefile in each subdirectory:

cur_makefile := $(lastword $(MAKEFILE_LIST))

Then each subdirectory's Makefile will have its own "cur_makefile" variable set to its own path relative to the root directory. For example, the Makefile in "project/dir1" will have "cur_makefile" set to "project/dir1/Makefile", and so on.

I hope these examples help clarify how the "cur_makefile" variable can be used in a Makefile. Let me know if you have any further questions!