The common.mk file

The common.mk include file is where you put the traditional makefile options, such as compiler options.

In order for the common.mk file to be able to determine which system to build the particular objects, libraries, or executables for, we analyze the pathname components in the bottommost level in reverse order as follows:

the last component is assigned to the VARIANT1 macro
the next previous component is assigned to the CPU macro
the next previous component is assigned to the OS macro
the next previous component is assigned to the SECTION macro
the next previous component is assigned to the PROJECT macro

For example, if we have a pathname of /source/factory/robot_plc/driver/nto/arm/o.le, then the macros are set as follows:

Macro	Value
`VARIANT1`	`o.be`
`CPU`	`arm`
`OS`	`nto`
`SECTION`	`driver`
`PROJECT`	`robot_plc`