Windows Cross broken.

The changes from the ghc-toolchain; appear to have resulted in broken configure for cross compilers. My GHC now reports:

x86_64-w64-mingw32-ghc --info
 [("Project name","The Glorious Glasgow Haskell Compilation System")
 ,("C compiler command","x86_64-w64-mingw32-cc")
 ,("C compiler flags",".")
 ,("C++ compiler command","x86_64-w64-mingw32-c++")
 ,("C++ compiler flags",".")

which then causes Hadrian to invoke:

x86_64-w64-mingw32-ghc -hide-all-packages -c /run/user/1000/1226304-0.c -o /run/user/1000/1226304-1.o -no-global-package-db '-package-db=_build/stage1/inplace/package.conf.d' '-ghcversion-file=rts/include/ghcversion.h' '-ghcversion-file=rts/include/ghcversion.h'

(not sure why it feels like it needs to pass ghcversion.h twice).

This subsequently ends up invoking the following amazing command:

x86_64-w64-mingw32-cc -x c -c /run/user/1000/1226304-0.c -o /run/user/1000/1226304-1.o.tmp -Wa,-mbig-obj -Wimplicit -include rts/include/ghcversion.h .

Note the . at the end.

This ultimately complains about

x86_64-w64-mingw32-gcc: fatal error: cannot specify '-o' with '-c', '-S' or '-E' with multiple files

/cc @alt-romes

---

the configure phase printed the following:

configure: WARNING:
There are some differences between the toolchain configured by "configure" (hadrian/cfg/default.target) and the toolchain configured by the "ghc-toolchain" program (hadrian/cfg/default.target.ghc-toolchain).

3c3
< , tgtVendor = Just "unknown"
---
> , tgtVendor = Just "w64"
18c18
< , tgtHsCPreprocessor = HsCpp {hsCppProgram = Program {prgPath = "x86_64-w64-mingw32-cc", prgFlags = ["-E","-undef","-traditional"]}}
---
> , tgtHsCPreprocessor = HsCpp {hsCppProgram = Program {prgPath = "x86_64-w64-mingw32-cc", prgFlags = ["-E","-undef","-traditional","-Wno-invalid-pp-token","-Wno-unicode","-Wno-trigraphs"]}}
20c20
< { ccLinkProgram = Program {prgPath = "x86_64-w64-mingw32-cc", prgFlags = ["-fstack-check"]}
---
> { ccLinkProgram = Program {prgPath = "x86_64-w64-mingw32-cc", prgFlags = ["-fuse-ld=gold","-fstack-check"]}
35c35
< , tgtRanlib = Just (Ranlib {ranlibProgram = Program {prgPath = "x86_64-w64-mingw32-ranlib", prgFlags = []}})
---
> , tgtRanlib = Just (Ranlib {ranlibProgram = Program {prgPath = "x86_64-w64-mingw32-ranlib", prgFlags = []}})
38c38
< , tgtWindres = Nothing
---
> , tgtWindres = Just (Program {prgPath = "x86_64-w64-mingw32-windres", prgFlags = []})

Don't worry! This won't affect your ghc in any way.
However, in a near future, we will move to configuring toolchains with "ghc-toolchain" by default, so you might have discovered a future bug.

(that message is fairly hard to parse, which file is left side, which one is right side of the diff?)