Makefile: Use standard variables and locations

Makefile: Use standard variables and locations

[Alejandro Colomar (man-pages)]

Hi Michael,

There are a few points I think we should fix in the Makefile:

- Use standard variables:
	* mandir (instead of MANDIR)
	* htmldir (instead of HTDIR)
	(see
<https://www.gnu.org/software/make/manual/html_node/Directory-Variables.html>)

- Use standard targets:
	* separate html into html and install-html
	* installdirs (instead of having 'mkdir -p'/'install -d' embedded in
targets)
	(see
<https://www.gnu.org/software/make/manual/html_node/Standard-Targets.html#Standard-Targets>)

- '?=' is not needed, I think.  When a user defines a variable in the
command line, that overwrites any definition in the Makefile.

- Is '|| exit $$?' really needed?  AFAIK, make exits on error.  Maybe
there's a corner case that make doesn't handle well and exit does,
though.  I don't know.

- Use $(INSTALL_DATA) instead of using install directly.

- Specify SHELL = /bin/sh


Any thoughts?

Cheers,

Alex

-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/

Re: Makefile: Use standard variables and locations

[Jakub Wilk]

* Alejandro Colomar <alx.manpages@gmail.com>, 2021-03-20, 22:03:
>- Is '|| exit $$?' really needed?  AFAIK, make exits on error.

Make catches errors, but shell doesn't by default. So if a recipe 
contains more than a simple command, you need to care of error handling 
yourself. For example:

   $ printf 'all:\n\tfalse; echo moo\n' > Makefile

   $ make
   false; echo moo
   moo

   $ echo $?
   0

>- Specify SHELL = /bin/sh

This is the default on Unix-like systems.

-- 
Jakub Wilk

Re: Makefile: Use standard variables and locations

[Alejandro Colomar (man-pages)]

Hi Jakub,

On 3/25/21 11:06 PM, Jakub Wilk wrote:
> * Alejandro Colomar <alx.manpages@gmail.com>, 2021-03-20, 22:03:
>> - Is '|| exit $$?' really needed?  AFAIK, make exits on error.
> 
> Make catches errors, but shell doesn't by default. So if a recipe
> contains more than a simple command, you need to care of error handling
> yourself. For example:
> 
>   $ printf 'all:\n\tfalse; echo moo\n' > Makefile
> 
>   $ make
>   false; echo moo
>   moo
> 
>   $ echo $?
>   0

Ahh, I see.

> 
>> - Specify SHELL = /bin/sh
> 
> This is the default on Unix-like systems.

Humm, yes, it feels better to not specify it.  I was just following GNU
recommendations, but this one doesn't make much sense.  I'll remove it.

Thanks,

Alex

-- 
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/