I think the OP is looking at quite an outdated version of the documentation.
The Readme at `chromium/3061` indeed says "use_sysroot = false # Currently must be false on Linux."
This has long since changed, and the easiest solution may be to build with the default `use_sysroot = true` if you don't mind using the external sysroot.
Otherwise, this probably points at missing base system headers/packages, as @hjanuschka also mentions.
Try conducting a "whatprovides" search with your package manager on the missing path(s) to figure out what packages exactly you need to install.
e.g. on my install of Fedora, `dnf whatprovides '*/asm/errno.h'` points at the "kernel-headers" package.