Previously, we did ./configure time checks to see if 'GNU ld' supported
certain options. If it does, we bake those options into the link step.
See Trac #5240.

Unfortunately, the linker we use at runtime can change for several
reasons. One is that the user specifies -pgml 'foo'. The other is if
/usr/bin/ld or whatnot changes from when GHC was built.  Those options
mentioned earlier are specific to GNU ld, but many systems support GNU
gold too. This is Trac #6063.

So we need to check at runtime what linker we're using. This is actually
a little bit complicated because we normally use the C compiler as our
linker. Windows and OS X are also special here.

Finally, this patch also unconditionally gives '--hash-size=31' and
'--reduce-memory-overheads' to the system linker if it's GNU ld. These
options have been supported for 8+ years from what I can see, and there
are probably a lot of other reasons why GHC would not work with such an
ancient binutils, all things considered.

See Note [Run-time linker info] in SysTools for details. There are
plenty of comments as well in the surrounding code.

Signed-off-by: Austin Seipp <aseipp@pobox.com>

It now just warns about files it doesn't recognise, rather than giving
an error. This means that random text files etc in the same directory
as the bindists don't make it fall over.

We now leave making installers to the Haskell Platform.

Without it, when linking the split objects for Language.Haskell.TH.Syntax,
the commandline was too long when listing all the files directly.

Makes it clearer whether it succeeded when redirecting output

It thought that something impossible was happening when they
were involved.

This program:

    main :: IO ()
    main = do re "[^ ]" "\207"
              re "[ ]" "\207"
              re " " "\207"

    re :: String -> String -> IO ()
    re r str = let r' = makeRegex r :: Regex
                   res = matchM r' str :: Maybe (String, String, String, [String])
               in print res

prints

    Nothing
    Nothing
    Nothing

for me with Posix, but

    Just ("","\207","",[])
    Nothing
    Nothing

with PCRE. This was causing compare to fail with

    Tar line doesn't parse: "drwxrwxr-x simonmar/GHC       0 2012-12-08 21:35 ghc-7.6.1.20121207/libraries/haskeline/tests/dummy-\206\188\206\177\207\\302\\203/"

on the GHC source tarball.

They are no longer used

We no longer produce installers fo OS X; we leave that to the Haskell
Platform team.

This required various build system changes to get the build to go
through.

In the inplace shell wrappers, we set LD_LIBRARY_PATH to allow programs
to find their libraries. In the future, we might change the inplace tree
to be the same shape as an installed tree instead. However, this would
mean changing the way we do installation, as currently we use cabal's
installation methods to install the libraries, but that only works if
the libraries are under libraries/foo/dist-install/build/..., rather
than in inplace/lib/...

Now that it's included in settings, the bindist configure script needs
to know it.

Related to #4862

Cabal no longer has a userguide that we know how to build, so we
can't include it in our docs.

Maybe we could revisit whether we want to allow building bindists of
cross-compilers later, but for now I'm fixing validate by setting all
the cross-compilation settings to NO.

We want to use the inplace ar, rather than whichever ar the
machine that we build on happens to have.

On XCode 4.1, we use /usr/bin/gcc-4.2 as it makes better code than
/usr/bin/gcc for us. However, gcc-4.2 doesn't exist in XCode 4.2, so we
need to use /usr/bin/gcc there. As the installer can be used on either,
we make it always use /usr/bin/gcc.

Now target32bit works for all targets without any manual intervention,
as it should do.  #5735 was a portability regression.

Some platforms use linkers that don't support the --hash-size=31 and
--reduce-memory-overheads flags.