The ISO9660 tests are currently using an old 2017 toolchain. Let's switch to a modern toolchain, which is regularly updated. Also, we use a toolchain based on glibc since grub2 doesn't build with recent uClibc toolchains. It will work around build issues with syslinux. Fixes: https://gitlab.com/buildroot.org/buildroot/-/jobs/10975828975 https://gitlab.com/buildroot.org/buildroot/-/jobs/10975828871 https://gitlab.com/buildroot.org/buildroot/-/jobs/10975828770 (Even though those should be fixed separately, as syslinux should continue to build with old compilers not supporting std=gnu17) Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Signed-off-by: Julien Olivain <ju.o@free.fr>