Help please! Suddenly my Windows build has stopped working. See below. What should I do? I'm totally stuck. This has never happened before. I get this: GHC path canonicalised to: c:/fp/ghc-8.0.2/bin/ghc checking build system type... x86_64-pc-msys checking host system type... x86_64-pc-msys checking target system type... x86_64-pc-msys Build platform inferred as: x86_64-unknown-mingw32 Host platform inferred as: x86_64-unknown-mingw32 Target platform inferred as: x86_64-unknown-mingw32 GHC build : x86_64-unknown-mingw32 GHC host : x86_64-unknown-mingw32 GHC target : x86_64-unknown-mingw32 LLVM target: x86_64-unknown-mingw32 checking for path to top of build tree... C:/code/HEAD configure: Checking for Windows toolchain tarballs... configure: Extracting Windows toolchain from archives (may take a while)... configure: In-tree MingW-w64 tree created configure: Making in-tree perl tree configure: In-tree perl tree created checking whether the C compiler works... no configure: error: in `/c/code/HEAD': configure: error: C compiler cannot create executables See `config.log' for more details Something wrong with the gcc.exe? Config.log has this gcc version 6.3.0 (Rev2, Built by MSYS2 project) configure:4950: $? = 0 configure:4939: C:/code/HEAD/inplace/mingw/bin/gcc.exe -V >&5 gcc.exe: error: unrecognized command line option '-V' gcc.exe: fatal error: no input files compilation terminated. configure:4950: $? = 1 configure:4939: C:/code/HEAD/inplace/mingw/bin/gcc.exe -qversion >&5 gcc.exe: error: unrecognized command line option '-qversion'; did you mean '--version'? gcc.exe: fatal error: no input files compilation terminated. configure:4950: $? = 1 configure:4970: checking whether the C compiler works configure:4992: C:/code/HEAD/inplace/mingw/bin/gcc.exe conftest.c >&5 configure:4996: $? = 1 configure:5034: result: no configure: failed program was: | /* confdefs.h */ | #define PACKAGE_NAME "The Glorious Glasgow Haskell Compilation System" | #define PACKAGE_TARNAME "ghc-8.3" | #define PACKAGE_VERSION "8.3" | #define PACKAGE_STRING "The Glorious Glasgow Haskell Compilation System 8.3" | #define PACKAGE_BUGREPORT "glasgow-haskell-bugs@haskell.org" | #define PACKAGE_URL "" | /* end confdefs.h. */ | | int | main () | { | | ; | return 0; | } configure:5039: error: in `/c/code/HEAD': configure:5041: error: C compiler cannot create executables