chroot/mount: create /dev/fd
Specifically, this fixes issues with process substitution in bash in the chroot.
For example, the following lines from a NetworkManager build script:
... |
grep -Fx -f <(get_symbols_explicit) -v |
grep -Fx -f <(get_symbols_nm)
fail with:
ninja: job failed: /home/pmos/build/src/NetworkManager-1.35.92/tools/create-exports-NetworkManager.sh --called-from-build /home/pmos/build/src/NetworkManager-1.35.92
grep: /dev/fd/63: No such file or directory
grep: /dev/fd/63: No such file or directory