Subject: cmake-build-system sets wrong CMAKE_SYSTEM_NAME when crossbuilding for Hurd
From: Dariqq <[email-masked]>
To: [email-masked]
Date: Sun, 18 Aug 2024 13:40:43 +0000
List-Id: <debbugs-submit.debbugs.gnu.org>

Hi,

I was playing around with a package using cmake and got an error when 
crossbuilding for i586-pc-gnu. The reason seems to be that cmake build 
system only checks for a mingw target and assumes all other targets are 
Linux and sets CMAKE_SYSTEM_NAME accordingly.

I am able to work around it by adding something like

#$@(if (and (%current-target-system)
	    target-hurd?)
        '("-DCMAKE_SYSTEM_NAME=GNU")
        '())

to the configure-flags of my package.

I am unsure how a fix should look like. I was thinking of moving the 
entire crossbuild code out of the build side and instead prepend the 
right configure flags for the target to configure-flags for the cross 
builder kind of similar how meson-build-system does it.

Unfortunately a change like this causes a lot of rebuilds.