yosys: show standalone use-case

[oharboe]

$ bazel build alu
INFO: Invocation ID: 8abc9dce-1f7a-4ffc-89fc-1405ce367437
INFO: Analyzed target //:alu (0 packages loaded, 0 targets configured).
ERROR: /home/oyvind/bazel-orfs/BUILD:460:8: Executing genrule //:alu failed: (Exit 127): bash failed: error executing Genrule command (from target //:alu) /bin/bash -c ... (remaining 1 argument skipped)

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
+ ldd external/_main~orfs_repositories~docker_orfs/OpenROAD-flow-scripts/tools/install/yosys/bin/yosys
+ external/_main~orfs_repositories~docker_orfs/OpenROAD-flow-scripts/tools/install/yosys/bin/yosys -p 'read_verilog ./alu.v; write_json bazel-out/k8-fastbuild/bin/alu.json'
/bin/bash: line 4: external/_main~orfs_repositories~docker_orfs/OpenROAD-flow-scripts/tools/install/yosys/bin/yosys: cannot execute: required file not found
	linux-vdso.so.1 (0x00007ffe55b6e000)
	libstdc++.so.6 => not found
	libm.so.6 => not found
	libreadline.so.8 => not found
	libffi.so.8 => not found
	libz.so.1 => not found
	libtcl8.6.so => not found
	libgcc_s.so.1 => not found
	libc.so.6 => not found
Target //:alu failed to build
Use --verbose_failures to see the command lines of failed build steps.
INFO: Elapsed time: 0.328s, Critical Path: 0.24s
INFO: 2 processes: 2 internal.
ERROR: Build did NOT complete successfully