can't validate on Linux

[Richard Eisenberg]

Hi devs,

When I try validating my patch, validation fails with

> ...
> Registering library for ghc-prim-0.5.0.0..
> ghc-cabal: '/home/rae/ghc/ghc-valid/bindisttest/install
> dir/lib/ghc-8.3.20170312/bin/ghc-pkg' exited with an error:
> ghc-pkg: Couldn't open database /home/rae/ghc/ghc-valid/bindisttest/install
> dir/lib/ghc-8.3.20170312/package.conf.d for modification: {handle:
> /home/rae/ghc/ghc-valid/bindisttest/install
> dir/lib/ghc-8.3.20170312/package.conf.d/package.cache.lock}: hLock: invalid
> argument (Bad file descriptor)
> make[3]: *** [ghc.mk:990: install_packages] Error 1
> make[2]: *** [Makefile:51: install] Error 2
> make[1]: *** [bindisttest/ghc.mk:33: test_bindist] Error 2
> make: *** [Makefile:127: test_bindist] Error 2

Any advice?

Thanks!
Richard