How do you comment your makefiles?

Fed up w/ my ad-hoc scripts to display the targets and variables in a makefile(s), I’ve decided to write a reusable piece of code to do that: github.com/bahmanm/bmakelib/issues/81

The first step toward that would be to understand the common commenting styles. So far I have identified 4 patterns in the wild which you can find below.

Are there any style guides/conventions around this topic? Any references to well-written makefiles I can get inspiration from?

A

<span style="color:#323232;">VAR1 = foo   ## short one-liner comment
</span><span style="color:#323232;">my-target:   ## short one-liner comment 
</span><span style="color:#323232;">	…
</span>

B

<span style="color:#323232;"># longer comment which 
</span><span style="color:#323232;"># may span
</span><span style="color:#323232;"># several lines
</span><span style="color:#323232;">VAR1 = foo
</span><span style="color:#323232;">
</span><span style="color:#323232;">## comments can be prefixed w/ more than # 
</span><span style="color:#323232;">## lorem ipsum dolor
</span><span style="color:#323232;">my-target: 
</span><span style="color:#323232;">	…
</span>

C

<span style="color:#323232;">#####
</span><span style="color:#323232;"># a comment block which is marked w/ several #s on
</span><span style="color:#323232;"># an otherwise blank line
</span><span style="color:#323232;">#####
</span><span style="color:#323232;">VAR1 = foo
</span>

D

<span style="color:#323232;">#####
</span><span style="color:#323232;">#>    # heading 1
</span><span style="color:#323232;">#     This is a variation to have markdown comments
</span><span style="color:#323232;">#     inside makefile comments.
</span><span style="color:#323232;">#
</span><span style="color:#323232;">#     ## It's a made-up style!  
</span><span style="color:#323232;">#     I came up w/ this style and used it to document `bmakelib`.
</span><span style="color:#323232;">#     For example: https://is.gd/QtiqyA (opens github)
</span><span style="color:#323232;">#&lt;
</span><span style="color:#323232;">#####
</span><span style="color:#323232;">VAR1 = foo
</span>