ghc has perl in closure

[domenkozar]

$ nix-store -qR `nix-build -A ghc`
/nix/store/5l472kj6h5zvccpzp0zcdpc1w2njfd58-linux-headers-3.12.32
/nix/store/hd6km3hscbgl2yw8nx7lr5z9s8h89p04-glibc-2.21
/nix/store/31w31mc8immhpnmxvcl4l0fvc3i5iwh0-zlib-1.2.8
/nix/store/xag5ayq906w9zhlxs8wayv4kvpiyqphq-bash-4.3-p42
/nix/store/4i01mpa2s194m44xrz41wmf4yr49jysq-ncurses-5.9
/nix/store/8z667vv1agvpd3iknmk94j0ix6bv413i-attr-2.4.47
/nix/store/sk0b1r840b686zc2m8mzyw8yyq1aymqh-acl-2.2.52
/nix/store/8xfxnm4a7jvyh0i1sd967z6rws8lh21a-coreutils-8.24
/nix/store/i9nn1fkcy95dzf0hb9wi8gbkid3iw1sa-gcc-4.9.3
/nix/store/kxf1p7l7lgm6j5mjzkiwcwzc98s9f1az-binutils-2.23.1
/nix/store/4n9yj90rdggqcx34ylbshryg3rf9cqpj-gcc-wrapper-4.9.3
/nix/store/a3x9hggwq83f3fk88lqvgh6jvlklhk36-perl-5.20.2
/nix/store/i4g323b60pskbayk4awl3ffz8m365264-gmp-5.1.3
/nix/store/7hnlpxpmpka84zrhyq7z11bs0q3vgak1-ghc-7.10.2

$ grep -R /nix/store/a3x9hggwq83f3fk88lqvgh6jvlklhk36-perl-5.20.2 /nix/store/7hnlpxpmpka84zrhyq7z11bs0q3vgak1-ghc-7.10.2
/nix/store/7hnlpxpmpka84zrhyq7z11bs0q3vgak1-ghc-7.10.2/lib/ghc-7.10.2/ghc-split:#!/nix/store/a3x9hggwq83f3fk88lqvgh6jvlklhk36-perl-5.20.2/bin/perl
/nix/store/7hnlpxpmpka84zrhyq7z11bs0q3vgak1-ghc-7.10.2/lib/ghc-7.10.2/settings: ("perl command", "/nix/store/a3x9hggwq83f3fk88lqvgh6jvlklhk36-perl-5.20.2/bin/perl"),

cc @peti

[edolstra]

Well, ghc-split really needs it, right?

[peti]

Yes, ghc-split is required, especially in Nixpkgs, because we use --enable-split-objs all over the place. I don't think that we can avoid perl.

[domenkozar]

OK, my bad then. Thanks for the explanation.

[domenkozar]

Well technically we could have a separate output for ghc-split that wouldn't be needed at runtime, but not sure if that's even feasible.

[vcunat]

GHC(I) is a compiler/interpreter, so I don't think it matters much for that to depend on perl, especially when ghc has ~1 GB by itself. However, if we have stuff only depending on so-libs from GHC, those do seem worth splitting out.