Re: [PATCH] Revert "make: let src/Makefile set *dir vars properly"

[Jens Axboe <axboe@kernel.dk>]

On 4/14/22 12:36 AM, Stefan Hajnoczi wrote:
> This reverts commit 9236f53a8ffe96cc2430f7131bbcba5756b97bc2.
> 
> "make install DESTDIR=..." specifies a root directory where files are
> installed. For example, includedir=/usr/include DESTDIR=/a should
> install header files into /a/usr/include.
> 
> Commit 9236f53a8ffe removed the includedir=, etc arguments on the make
> command-line in ./Makefile, leaving only prefix=$(DESTDIR)$(prefix). It
> claimed "prefix suffice for setting *dir variables in src/Makefile" but
> this is incorrect. "make install DESTDIR=..." now has no effect and
> files are not installed with a DESTDIR prefix.
> 
> The GNU make manual 9.5 Overriding Variables says:
> 
>   all ordinary assignments of the same variable in the makefile are
>   ignored; we say they have been overridden by the command line
>   argument.
> 
> This explains why it was necessary to set includedir=, etc on the make
> command-line in ./Makefile. We need to override these variables with
> DESTDIR from the command-line so they are not clobbered in src/Makefile
> when config-host.mak is included.

I think this should have gone to io-uring@vger.kernel.org, the patch had
me confused for a second.

-- 
Jens Axboe