When syslinux 6.03 is constructed using the linker ld.gold no error is obtained in this process. Installing syslinux on a disk does not show any error, but booting with the disk fails.
When syslinux 6.03 is constructed with linker ld.bfd everything works fine.
Created attachment 418096 [details, diff]
Confirmed. Extlinux 6.03, built using the Gold linker from sys-devel/binutils-2.25.1-r1 on ~amd64, hangs on boot immediately after the "EXTLINUX" version line. No error message is displayed. After rebuilding sys-boot/syslinux-6.03 using the BFD linker and reinstalling Extlinux on the boot file system, boot proceeds correctly.
This bug should have CRITICAL priority because it could cause a remotely administrated server to fail to boot after an upgrade. (I'm lucky that I have physical access to the machine that I broke by upgrading to this version of Extlinux.)
At the very least, the ebuild should be made to error out if the default linker is Gold. A better solution would be for the ebuild to call tc-ld-disable-gold. The attached ebuild patch makes this change and solves the problem.
syslinux-6.03 and 6.04_pre1 now include a ld.gold check (can be overridden with I_KNOW_WHAT_I_AM_DOING=1).
Leaving this bug open until the underlying issue is fixed.
Please also report this upstream.