Pass user-defined-trusted-dirs to glibc

[bedroge]

We probably may need/use this for the CUDA support (see EESSI/compatibility-layer#71), and possibly other use cases.

This can be done by modifying the glibc ebuild, but this is a bit cumbersome, since it has to be redone for every new version. We could, instead, use the following approach, which allows us to override variables per package (or even per version of a package):
https://groups.google.com/g/linux.gentoo.user/c/z1ZXuJkd0ro/m/9PUWFv8BXnUJ

I quickly tested it by adding a $EPREFIX/etc/portage/bashrc:

for MY_ENV in ${PN} ${P} ${PF}; do 
	if [ -f ${EPREFIX}/etc/portage/env.d/${CATEGORY}/${MY_ENV} ]; then 
		. ${EPREFIX}/etc/portage/env.d/${CATEGORY}/${MY_ENV} 
		fi 
	done

and a file $EPREFIX/etc/portage/env.d/sys-libc/glibc:

EXTRA_ECONF="--testme"

Running emerge --ask --verbose sys-libs/glibc then failed, as expected:

configure: error: unrecognized option: `--testme'

This can be easily included in the etc/portage dir of this repo, as our compatibility layer playbook already makes symlinks in ${EPREFIX}/etc/portage to all files/dirs in this directory.

[bedroge]

Hmm, seems like user-defined-trusted-dirs is not a configure parameter... let's see if there is a similar variable that we can use for the make step.

[ocaisa]

Looks like there might be EXTRA_EMAKE

[bedroge]

Indeed, but it doesn't seem to be picked up by glibc for some reason. There's also MAKEOPTS, which is usually used for setting the number of threads (eg -j2), which we can abuse for this purpose, but it may be a bit ugly...

[bedroge]

Passing EXTRA_EMAKE on the command-line instead of via that file does work, strange...

[bedroge]

Okay, the following does seem to work (based on this https://wiki.gentoo.org/wiki//etc/portage/package.env):

$ cat $EPREFIX/etc/portage/package.env
sys-libs/glibc glibc-user-defined-trusted-dirs.conf

$ cat $EPREFIX/etc/portage/env/glibc-user-defined-trusted-dirs.conf
EXTRA_EMAKE="user-defined-trusted-dirs=/opt/eessi/lib64"

Running emerge --ask --verbose sys-libs/glibc then shows:

make -j2 -C /tmp/gentoo/var/tmp/portage/sys-libs/glibc-2.32-r7/work/build-amd64-x86_64-pc-linux-gnu-nptl user-defined-trusted-dirs=/opt/eessi/lib64 

[bedroge]

Reopening this issue, since I don't think this worked. For my test installation I saw this:

$ strings /cvmfs/pilot.eessi-hpc.org/2021.02/compat/linux/x86_64/usr/lib64/libc.a | grep "/opt/eessi"
/opt/eessi/lib/

But with our current installations this doesn't return anything, neither for lib64/{libc.so.6,ld-linux-x86-64.so.2}.