makefile if

In a Makefile, the `if` statement is used to conditionally execute certain commands based on a condition. Here's an example:

ifeq ($(VAR), value)
    # Commands to execute if VAR is equal to value
else
    # Commands to execute if VAR is not equal to value
endif

In this example, `$(VAR)` is a variable whose value is being checked against "value". If `$(VAR)` is equal to "value", the commands between the `ifeq` and `else` statements will be executed. Otherwise, the commands between the `else` and `endif` statements will be executed.

You can use various comparison operators such as `eq`, `neq`, `gt`, `lt`, etc., to perform different types of comparisons in the `ifeq` statement.