Latest rust build failure on amd64

[Paul Goyette <paul%whooppee.com@localhost>]

On a 8.99.7 host, I'm trying to install the latest updates to my ~600 
packages.  I've rebuilt more than 575 of them successfully, but I'm 
stuck with the following error.  My pkgsrc tree is updated on 2017-12-30 
at 21:35:57 UTC

Here's the last bit of my log:

...
     Running `/tmp/pkgs/lang/rust/work.x86_64/rustc-1.22.1-src/build/bootstrap/debug/rustc --crate-name bitflags src/vendor/bitflags-0.8.2/src/lib.rs --crate-type lib --emit=dep-info,link -C opt-level=2 -C metadata=05aadb2462765ecd -C extra-filename=-05aadb2462765ecd --out-dir /tmp/pkgs/lang/rust/work.x86_64/rustc-1.22.1-src/build/x86_64-unknown-netbsd/stage2-tools/x86_64-unknown-netbsd/release/deps --target x86_64-unknown-netbsd -L dependency=/tmp/pkgs/lang/rust/work.x86_64/rustc-1.22.1-src/build/x86_64-unknown-netbsd/stage2-tools/x86_64-unknown-netbsd/release/deps -L dependency=/tmp/pkgs/lang/rust/work.x86_64/rustc-1.22.1-src/build/x86_64-unknown-netbsd/stage2-tools/release/deps --cap-lints allow`
error: build failed


command did not execute successfully: "/tmp/pkgs/lang/rust/work.x86_64/rust-bootstrap/bin/cargo" "build" "--target" "x86_64-unknown-netbsd" "-v" "--release" "--frozen" "--manifest-path" "/tmp/pkgs/lang/rust/work.x86_64/rustc-1.22.1-src/src/tools/rustdoc/Cargo.toml"
expected success, got: exit code: 101


Traceback (most recent call last):
  File "./x.py", line 20, in <module>
    bootstrap.main()
  File "/tmp/pkgs/lang/rust/work.x86_64/rustc-1.22.1-src/src/bootstrap/bootstrap.py", line 756, in main
    bootstrap()
  File "/tmp/pkgs/lang/rust/work.x86_64/rustc-1.22.1-src/src/bootstrap/bootstrap.py", line 747, in bootstrap
    run(args, env=env, verbose=build.verbose)
  File "/tmp/pkgs/lang/rust/work.x86_64/rustc-1.22.1-src/src/bootstrap/bootstrap.py", line 148, in run
    raise RuntimeError(err)
RuntimeError: failed to run: /tmp/pkgs/lang/rust/work.x86_64/rustc-1.22.1-src/build/bootstrap/debug/bootstrap -v dist
*** Error code 1

Stop.
make[1]: stopped in /build/pkgsrc/lang/rust
*** Error code 1

Stop.
make: stopped in /build/pkgsrc/lang/rust




+------------------+--------------------------+----------------------------+
| Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:          |
| (Retired)        | FA29 0E3B 35AF E8AE 6651 | paul at whooppee dot com   |
| Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd dot org |
+------------------+--------------------------+----------------------------+