Use $CONFIGURE_ARGS or configure_ghc

[JakobBruenker]

ghc.nix recommends using ./configure $CONFIGURE_ARGS, and also provides a convenience command configure_ghc which does the same.

It seems like would make sense to recommend one of these here instead of a naked ./configure, which is the case at the moment.

[steshaw]

I was curious about that too. I wasn't sure if ghc.dev was out of date compared with the ghc.nix, or if ghc.dev does not recommend using those configure options. FWIW, I just followed the method from Building the Compiler and everything seemed to go okay 👍.

On my machine, the message from nix-shell ../ghc.nix is:

Recommended ./configure arguments (found in $CONFIGURE_ARGS:
or use the configure_ghc command):

  --with-gmp-includes=/nix/store/b8z6nbydvkdflfkk6924zdn9hzxiy45r-gmp-6.2.0-dev/include
  --with-gmp-libraries=/nix/store/1lj2b24v408awrfxw6xxv9spm9023lva-gmp-6.2.0/lib
  --with-curses-libraries=/nix/store/2dfap74q83z6q1kc9ha6ldl4nmqhmc9w-ncurses-6.2/lib
  --with-libnuma-includes=/nix/store/5yi02q15si6cg7w08hs85mvb3fr5pj4x-numactl-2.0.13/include
  --with-libnuma-libraries=/nix/store/5yi02q15si6cg7w08hs85mvb3fr5pj4x-numactl-2.0.13/lib
  --with-libdw-includes=/nix/store/v9cfb4dhh1cy6njixy0b7vxgk56k07bk-elfutils-0.180/include
  --with-libdw-libraries=/nix/store/v9cfb4dhh1cy6njixy0b7vxgk56k07bk-elfutils-0.180/lib
  --enable-dwarf-unwind

The configure_ghc is defined as:

$ typeset -f configure_ghc
configure_ghc () 
{ 
    ./configure $CONFIGURE_ARGS $@
}

A couple of questions:

• Where do I look to find the configuration that ./configure automatically deciphered.
• How can I clean build my GHC using configure_ghc as recommended by ghc.nix

[JakobBruenker]

I just followed the method from Building the Compiler and everything seemed to go okay +1.

Everything works fine as long as you're in the nix-shell. If you try to use the compiled ghc binaries outside of it, they will complain about missing shared libraries (whereas they don't with configure_ghc), though they will still partially work.

[JakobBruenker]

$CONFIGURE_ARGS is probably better than configure_ghc, since non-nix users should be able to use the former without issues.

One caveat though is that in zsh, one would have to write ${=CONFIGURE_ARGS} instead of $CONFIGURE_ARGS

So, neither option is a silver bullet, unfortunately.