Merge pull request #40996 from obsidiansystems/cross-ghc

ghc, haskell-infra: #40929 take 2

pkgs/development/compilers/ghc/7.10.3.nix

···
 , # Whether to build dynamic libs for the standard library (on the target
   # platform). Static libs are always built.
   enableShared ? true
+
+, # What flavour to build. An empty string indicates no
+  # specific flavour and falls back to ghc default values.
+  ghcFlavour ? stdenv.lib.optionalString (targetPlatform != hostPlatform) "perf-cross"
 }:
 
 assert !enableIntegerSimple -> gmp != null;
···
   };
 
   buildMK = ''
+    BuildFlavour = ${ghcFlavour}
+    ifneq \"\$(BuildFlavour)\" \"\"
+    include mk/flavours/\$(BuildFlavour).mk
+    endif
     DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
   '' + stdenv.lib.optionalString enableIntegerSimple ''
     INTEGER_LIBRARY = integer-simple
   '' + stdenv.lib.optionalString (targetPlatform != hostPlatform) ''
-    BuildFlavour = perf-cross
     Stage1Only = YES
     HADDOCK_DOCS = NO
   '' + stdenv.lib.optionalString enableRelocatedStaticLibs ''
···
   targetCC = builtins.head toolsForTarget;
 
 in
-
 stdenv.mkDerivation rec {
   version = "7.10.3";
   name = "${targetPrefix}ghc-${version}";
···
     docFixes
     ./relocation.patch
   ];
+
+  postPatch = "patchShebangs .";
 
   # GHC is a bit confused on its cross terminology.
   preConfigure = ''
···
     export RANLIB="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}ranlib"
     export READELF="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}readelf"
     export STRIP="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}strip"
+
     echo -n "${buildMK}" > mk/build.mk
     sed -i -e 's|-isysroot /Developer/SDKs/MacOSX10.5.sdk||' configure
   '' + stdenv.lib.optionalString (!stdenv.isDarwin) ''
···
   crossConfig = true;
 
   nativeBuildInputs = [
-    ghc perl libxml2 libxslt docbook_xsl docbook_xml_dtd_45 docbook_xml_dtd_42 hscolour
+    perl libxml2 libxslt docbook_xsl docbook_xml_dtd_45 docbook_xml_dtd_42
+    ghc hscolour
   ];
 
   # For building runtime libs

pkgs/development/compilers/ghc/8.0.2.nix

···
 , # Whether to build dynamic libs for the standard library (on the target
   # platform). Static libs are always built.
   enableShared ? true
+
+, # What flavour to build. An empty string indicates no
+  # specific flavour and falls back to ghc default values.
+  ghcFlavour ? stdenv.lib.optionalString (targetPlatform != hostPlatform) "perf-cross"
 }:
 
 assert !enableIntegerSimple -> gmp != null;
···
     "${targetPlatform.config}-";
 
   buildMK = ''
+    BuildFlavour = ${ghcFlavour}
+    ifneq \"\$(BuildFlavour)\" \"\"
+    include mk/flavours/\$(BuildFlavour).mk
+    endif
     DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
   '' + stdenv.lib.optionalString enableIntegerSimple ''
     INTEGER_LIBRARY = integer-simple
   '' + stdenv.lib.optionalString (targetPlatform != hostPlatform) ''
-    BuildFlavour = perf-cross
     Stage1Only = YES
     HADDOCK_DOCS = NO
   '' + stdenv.lib.optionalString enableRelocatedStaticLibs ''
···
     ++ stdenv.lib.optional stdenv.isDarwin ./ghc-8.0.2-no-cpp-warnings.patch
     ++ stdenv.lib.optional stdenv.isDarwin ./backport-dylib-command-size-limit.patch;
 
+  postPatch = "patchShebangs .";
+
   # GHC is a bit confused on its cross terminology.
   preConfigure = ''
     for env in $(env | grep '^TARGET_' | sed -E 's|\+?=.*||'); do
···
     export RANLIB="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}ranlib"
     export READELF="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}readelf"
     export STRIP="${targetCC.bintools.bintools}/bin/${targetCC.bintools.targetPrefix}strip"
+
     echo -n "${buildMK}" > mk/build.mk
     sed -i -e 's|-isysroot /Developer/SDKs/MacOSX10.5.sdk||' configure
   '' + stdenv.lib.optionalString (!stdenv.isDarwin) ''
···
   # masss-rebuild.
   crossConfig = true;
 
-  nativeBuildInputs = [ ghc perl hscolour sphinx ];
+  nativeBuildInputs = [
+    perl sphinx
+    ghc hscolour
+  ];
 
   # For building runtime libs
   depsBuildTarget = toolsForTarget;
···
   # that in turn causes GHCi to abort
   stripDebugFlags = [ "-S" ] ++ stdenv.lib.optional (!targetPlatform.isDarwin) "--keep-file-symbols";
 
-  # zsh and other shells are smart about `{ghc}` but bash isn't, and doesn't
-  # treat that as a unary `{x,y,z,..}` repetition.
   postInstall = ''
-    paxmark m $out/lib/${name}/bin/${if targetPlatform != hostPlatform then "ghc" else "{ghc,haddock}"}
+    for bin in "$out"/lib/${name}/bin/*; do
+      isELF "$bin" || continue
+      paxmark m "$bin"
+    done
 
     # Install the bash completion file.
     install -D -m 444 utils/completion/ghc.bash $out/share/bash-completion/completions/${targetPrefix}ghc

pkgs/development/compilers/ghc/8.2.2.nix

···
 
 , # Whether to build dynamic libs for the standard library (on the target
   # platform). Static libs are always built.
-  enableShared ?
-    !(targetPlatform.isDarwin
-      # On iOS, dynamic linking is not supported
-      && (targetPlatform.isAarch64 || targetPlatform.isAarch32))
+  enableShared ? true
+
+, # What flavour to build. An empty string indicates no
+  # specific flavour and falls back to ghc default values.
+  ghcFlavour ? stdenv.lib.optionalString (targetPlatform != hostPlatform) "perf-cross"
 , # Whether to backport https://phabricator.haskell.org/D4388 for
   # deterministic profiling symbol names, at the cost of a slightly
   # non-standard GHC API
···
     "${targetPlatform.config}-";
 
   buildMK = ''
+    BuildFlavour = ${ghcFlavour}
+    ifneq \"\$(BuildFlavour)\" \"\"
+    include mk/flavours/\$(BuildFlavour).mk
+    endif
     DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
   '' + stdenv.lib.optionalString enableIntegerSimple ''
     INTEGER_LIBRARY = integer-simple
   '' + stdenv.lib.optionalString (targetPlatform != hostPlatform) ''
-    BuildFlavour = perf-cross
     Stage1Only = YES
     HADDOCK_DOCS = NO
     BUILD_SPHINX_HTML = NO
···
   # masss-rebuild.
   crossConfig = true;
 
-  nativeBuildInputs = [ alex autoconf autoreconfHook automake ghc happy hscolour perl python3 sphinx ];
+  nativeBuildInputs = [
+    autoconf autoreconfHook automake perl python3 sphinx
+    ghc alex happy hscolour
+  ];
 
   # For building runtime libs
   depsBuildTarget = toolsForTarget;
···
 
   checkTarget = "test";
 
-  # zsh and other shells are smart about `{ghc}` but bash isn't, and doesn't
-  # treat that as a unary `{x,y,z,..}` repetition.
   postInstall = ''
-    paxmark m $out/lib/${name}/bin/${if targetPlatform != hostPlatform then "ghc" else "{ghc,haddock}"}
+    for bin in "$out"/lib/${name}/bin/*; do
+      isELF "$bin" || continue
+      paxmark m "$bin"
+    done
 
     # Install the bash completion file.
     install -D -m 444 utils/completion/ghc.bash $out/share/bash-completion/completions/${targetPrefix}ghc

pkgs/development/compilers/ghc/8.4.2.nix

···
 
 # build-tools
 , bootPkgs, alex, happy
-, autoconf, automake, coreutils, fetchurl, fetchpatch, perl, python3
+, autoconf, automake, coreutils, fetchurl, fetchpatch, perl, python3, m4
 
 , libffi, libiconv ? null, ncurses
 
···
 
 , # If enabled, GHC will be built with the GPL-free but slower integer-simple
   # library instead of the faster but GPLed integer-gmp library.
-  enableIntegerSimple ? false, gmp ? null, m4
+  enableIntegerSimple ? false, gmp ? null
 
 , # If enabled, use -fPIC when compiling static libs.
   enableRelocatedStaticLibs ? targetPlatform != hostPlatform
 
 , # Whether to build dynamic libs for the standard library (on the target
   # platform). Static libs are always built.
-  enableShared ? !targetPlatform.useAndroidPrebuilt
+  enableShared ? !targetPlatform.isWindows && !targetPlatform.useAndroidPrebuilt
 
-, version ? "8.4.2"
+, # Whetherto build terminfo.
+  enableTerminfo ? !targetPlatform.isWindows
+
+, # What flavour to build. An empty string indicates no
+  # specific flavour and falls back to ghc default values.
+  ghcFlavour ? stdenv.lib.optionalString (targetPlatform != hostPlatform) "perf-cross"
 }:
 
 assert !enableIntegerSimple -> gmp != null;
···
     "${targetPlatform.config}-";
 
   buildMK = ''
+    BuildFlavour = ${ghcFlavour}
+    ifneq \"\$(BuildFlavour)\" \"\"
+    include mk/flavours/\$(BuildFlavour).mk
+    endif
     DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
   '' + stdenv.lib.optionalString enableIntegerSimple ''
     INTEGER_LIBRARY = integer-simple
   '' + stdenv.lib.optionalString (targetPlatform != hostPlatform) ''
-    BuildFlavour = perf-cross
     Stage1Only = YES
     HADDOCK_DOCS = NO
     BUILD_SPHINX_HTML = NO
···
   '';
 
   # Splicer will pull out correct variations
-  libDeps = platform: [ ncurses ]
+  libDeps = platform: stdenv.lib.optional enableTerminfo [ ncurses ]
     ++ stdenv.lib.optional (!enableIntegerSimple) gmp
-    ++ stdenv.lib.optional (platform.libc != "glibc") libiconv;
+    ++ stdenv.lib.optional (platform.libc != "glibc" && !targetPlatform.isWindows) libiconv;
 
   toolsForTarget =
     if hostPlatform == buildPlatform then
···
 
 in
 stdenv.mkDerivation rec {
-  inherit version;
+  version = "8.4.2";
   name = "${targetPrefix}ghc-${version}";
 
   src = fetchurl {
···
     "--with-curses-includes=${ncurses.dev}/include" "--with-curses-libraries=${ncurses.out}/lib"
   ] ++ stdenv.lib.optional (targetPlatform == hostPlatform && ! enableIntegerSimple) [
     "--with-gmp-includes=${gmp.dev}/include" "--with-gmp-libraries=${gmp.out}/lib"
-  ] ++ stdenv.lib.optional (targetPlatform == hostPlatform && hostPlatform.libc != "glibc") [
+  ] ++ stdenv.lib.optional (targetPlatform == hostPlatform && hostPlatform.libc != "glibc" && !targetPlatform.isWindows) [
     "--with-iconv-includes=${libiconv}/include" "--with-iconv-libraries=${libiconv}/lib"
   ] ++ stdenv.lib.optionals (targetPlatform != hostPlatform) [
     "--enable-bootstrap-with-devel-snapshot"
···
   # masss-rebuild.
   crossConfig = true;
 
-  nativeBuildInputs = [ ghc perl autoconf automake m4 happy alex python3 ];
+  nativeBuildInputs = [
+    perl autoconf automake m4 python3
+    ghc alex happy
+  ];
 
   # For building runtime libs
   depsBuildTarget = toolsForTarget;
···
 
   checkTarget = "test";
 
-  # zsh and other shells are smart about `{ghc}` but bash isn't, and doesn't
-  # treat that as a unary `{x,y,z,..}` repetition.
   postInstall = ''
-    paxmark m $out/lib/${name}/bin/${if targetPlatform != hostPlatform then "ghc" else "{ghc,haddock}"}
+    for bin in "$out"/lib/${name}/bin/*; do
+      isELF "$bin" || continue
+      paxmark m "$bin"
+    done
 
     # Install the bash completion file.
     install -D -m 444 utils/completion/ghc.bash $out/share/bash-completion/completions/${targetPrefix}ghc

pkgs/development/compilers/ghc/head.nix

···
 
 # build-tools
 , bootPkgs, alex, happy
-, autoconf, automake, coreutils, fetchgit, perl, python3
+, autoconf, automake, coreutils, fetchgit, perl, python3, m4
 
 , libffi, libiconv ? null, ncurses
 
···
 
 , # Whether to build dynamic libs for the standard library (on the target
   # platform). Static libs are always built.
-  enableShared ? !targetPlatform.useAndroidPrebuilt
+  enableShared ? !targetPlatform.isWindows && !targetPlatform.useAndroidPrebuilt
+
+, # Whetherto build terminfo.
+  enableTerminfo ? !targetPlatform.isWindows
 
 , version ? "8.5.20180118"
+, # What flavour to build. An empty string indicates no
+  # specific flavour and falls back to ghc default values.
+  ghcFlavour ? stdenv.lib.optionalString (targetPlatform != hostPlatform) "perf-cross"
 }:
 
 assert !enableIntegerSimple -> gmp != null;
···
     "${targetPlatform.config}-";
 
   buildMK = ''
+    BuildFlavour = ${ghcFlavour}
+    ifneq \"\$(BuildFlavour)\" \"\"
+    include mk/flavours/\$(BuildFlavour).mk
+    endif
     DYNAMIC_GHC_PROGRAMS = ${if enableShared then "YES" else "NO"}
   '' + stdenv.lib.optionalString enableIntegerSimple ''
     INTEGER_LIBRARY = integer-simple
   '' + stdenv.lib.optionalString (targetPlatform != hostPlatform) ''
-    BuildFlavour = perf-cross
     Stage1Only = YES
     HADDOCK_DOCS = NO
     BUILD_SPHINX_HTML = NO
···
   '';
 
   # Splicer will pull out correct variations
-  libDeps = platform: [ ncurses ]
+  libDeps = platform: stdenv.lib.optional enableTerminfo [ ncurses ]
     ++ stdenv.lib.optional (!enableIntegerSimple) gmp
-    ++ stdenv.lib.optional (platform.libc != "glibc") libiconv;
+    ++ stdenv.lib.optional (platform.libc != "glibc" && !targetPlatform.isWindows) libiconv;
 
   toolsForTarget =
     if hostPlatform == buildPlatform then
···
     "--with-curses-includes=${ncurses.dev}/include" "--with-curses-libraries=${ncurses.out}/lib"
   ] ++ stdenv.lib.optional (targetPlatform == hostPlatform && ! enableIntegerSimple) [
     "--with-gmp-includes=${gmp.dev}/include" "--with-gmp-libraries=${gmp.out}/lib"
-  ] ++ stdenv.lib.optional (targetPlatform == hostPlatform && hostPlatform.libc != "glibc") [
+  ] ++ stdenv.lib.optional (targetPlatform == hostPlatform && hostPlatform.libc != "glibc" && !targetPlatform.isWindows) [
     "--with-iconv-includes=${libiconv}/include" "--with-iconv-libraries=${libiconv}/lib"
   ] ++ stdenv.lib.optionals (targetPlatform != hostPlatform) [
     "--enable-bootstrap-with-devel-snapshot"
···
   # masss-rebuild.
   crossConfig = true;
 
-  nativeBuildInputs = [ ghc perl autoconf automake happy alex python3 ];
+  nativeBuildInputs = [
+    perl autoconf automake m4 python3
+    ghc alex happy
+  ];
 
   # For building runtime libs
   depsBuildTarget = toolsForTarget;
···
 
   checkTarget = "test";
 
-  # zsh and other shells are smart about `{ghc}` but bash isn't, and doesn't
-  # treat that as a unary `{x,y,z,..}` repetition.
   postInstall = ''
-    paxmark m $out/lib/${name}/bin/${if targetPlatform != hostPlatform then "ghc" else "{ghc,haddock}"}
+    for bin in "$out"/lib/${name}/bin/*; do
+      isELF "$bin" || continue
+      paxmark m "$bin"
+    done
 
     # Install the bash completion file.
     install -D -m 444 utils/completion/ghc.bash $out/share/bash-completion/completions/${targetPrefix}ghc

pkgs/development/haskell-modules/configuration-nix.nix

···
 
   # Prevents needing to add security_tool as a build tool to all of x509-system's
   # dependencies.
-  x509-system = if pkgs.stdenv.isDarwin && !pkgs.stdenv.cc.nativeLibc
+  x509-system = if pkgs.stdenv.targetPlatform.isDarwin && !pkgs.stdenv.cc.nativeLibc
     then let inherit (pkgs.darwin) security_tool;
       in pkgs.lib.overrideDerivation (addBuildDepend super.x509-system security_tool) (drv: {
         postPatch = (drv.postPatch or "") + ''

pkgs/development/haskell-modules/generic-builder.nix

···
 , buildTarget ? ""
 , buildTools ? [], libraryToolDepends ? [], executableToolDepends ? [], testToolDepends ? [], benchmarkToolDepends ? []
 , configureFlags ? []
+, buildFlags ? []
 , description ? ""
 , doCheck ? !isCross && stdenv.lib.versionOlder "7.4" ghc.version
 , doBenchmark ? false
···
 , enableSharedExecutables ? false
 , enableSharedLibraries ? ((ghc.isGhcjs or false) || stdenv.lib.versionOlder "7.7" ghc.version)
 , enableDeadCodeElimination ? (!stdenv.isDarwin)  # TODO: use -dead_strip for darwin
-, enableStaticLibraries ? true
+, enableStaticLibraries ? !hostPlatform.isWindows
 , enableHsc2hsViaAsm ? hostPlatform.isWindows && stdenv.lib.versionAtLeast ghc.version "8.4"
 , extraLibraries ? [], librarySystemDepends ? [], executableSystemDepends ? []
 , homepage ? "http://hackage.haskell.org/package/${pname}"
···
 } @ args:
 
 assert editedCabalFile != null -> revision != null;
+
+# --enable-static does not work on windows. This is a bug in GHC.
+# --enable-static will pass -staticlib to ghc, which only works for mach-o and elf.
+assert hostPlatform.isWindows -> enableStaticLibraries == false;
 
 let
 
···
 
   crossCabalFlagsString =
     stdenv.lib.optionalString isCross (" " + stdenv.lib.concatStringsSep " " crossCabalFlags);
+
+  buildFlagsString = optionalString (buildFlags != []) (" " + concatStringsSep " " buildFlags);
 
   defaultConfigureFlags = [
     "--verbose" "--prefix=$out" "--libdir=\\$prefix/lib/\\$compiler" "--libsubdir=\\$pkgid"
···
                         optionals doCheck testPkgconfigDepends ++ optionals doBenchmark benchmarkPkgconfigDepends;
 
   nativeBuildInputs = [ ghc nativeGhc removeReferencesTo ] ++ optional (allPkgconfigDepends != []) pkgconfig ++
+                      setupHaskellDepends ++
                       buildTools ++ libraryToolDepends ++ executableToolDepends;
   propagatedBuildInputs = buildDepends ++ libraryHaskellDepends ++ executableHaskellDepends;
-  otherBuildInputs = setupHaskellDepends ++ extraLibraries ++ librarySystemDepends ++ executableSystemDepends ++
+  otherBuildInputs = extraLibraries ++ librarySystemDepends ++ executableSystemDepends ++
                      allPkgconfigDepends ++
                      optionals doCheck (testDepends ++ testHaskellDepends ++ testSystemDepends ++ testToolDepends) ++
                      optionals doBenchmark (benchmarkDepends ++ benchmarkHaskellDepends ++ benchmarkSystemDepends ++ benchmarkToolDepends);
+
   allBuildInputs = propagatedBuildInputs ++ otherBuildInputs;
 
   haskellBuildInputs = stdenv.lib.filter isHaskellPkg allBuildInputs;
   systemBuildInputs = stdenv.lib.filter isSystemPkg allBuildInputs;
 
-  ghcEnv = ghc.withPackages (p: haskellBuildInputs);
+  # When not cross compiling, also include Setup.hs dependencies.
+  ghcEnv = ghc.withPackages (p:
+    haskellBuildInputs ++ stdenv.lib.optional (!isCross) setupHaskellDepends);
 
   setupCommand = "./Setup";
 
···
 
   nativeGhcCommand = "${nativeGhc.targetPrefix}ghc";
 
+  buildPkgDb = ghcName: ''
+    if [ -d "$p/lib/${ghcName}/package.conf.d" ]; then
+      cp -f "$p/lib/${ghcName}/package.conf.d/"*.conf $packageConfDir/
+      continue
+    fi
+    if [ -d "$p/include" ]; then
+      configureFlags+=" --extra-include-dirs=$p/include"
+    fi
+    if [ -d "$p/lib" ]; then
+      configureFlags+=" --extra-lib-dirs=$p/lib"
+    fi
+    if [[ -d "$p/Library/Frameworks" ]]; then
+      configureFlags+=" --extra-framework-dirs=$p/Library/Frameworks"
+    fi
+  '';
+
 in
 
 assert allPkgconfigDepends != [] -> pkgconfig != null;
···
     echo "Build with ${ghc}."
     ${optionalString (hasActiveLibrary && hyperlinkSource) "export PATH=${hscolour}/bin:$PATH"}
 
+  '' + (optionalString (setupHaskellDepends != []) ''
+    setupPackageConfDir="$TMPDIR/setup-package.conf.d"
+    mkdir -p $setupPackageConfDir
+  '') + ''
     packageConfDir="$TMPDIR/package.conf.d"
     mkdir -p $packageConfDir
 
     setupCompileFlags="${concatStringsSep " " setupCompileFlags}"
     configureFlags="${concatStringsSep " " defaultConfigureFlags} $configureFlags"
+  ''
+  # We build the Setup.hs on the *build* machine, and as such should only add
+  # dependencies for the build machine.
+  #
+  # pkgs* arrays defined in stdenv/setup.hs
+  + (optionalString (setupHaskellDepends != []) ''
+    for p in "''${pkgsBuildBuild[@]}" "''${pkgsBuildHost[@]}" "''${pkgsBuildTarget[@]}"; do
+      ${buildPkgDb nativeGhc.name}
+    done
+    ${nativeGhcCommand}-pkg --${nativePackageDbFlag}="$setupPackageConfDir" recache
+  '')
 
-    # host.*Pkgs defined in stdenv/setup.hs
+    # For normal components
+  + ''
     for p in "''${pkgsHostHost[@]}" "''${pkgsHostTarget[@]}"; do
-      if [ -d "$p/lib/${ghc.name}/package.conf.d" ]; then
-        cp -f "$p/lib/${ghc.name}/package.conf.d/"*.conf $packageConfDir/
-        continue
-      fi
-      if [ -d "$p/include" ]; then
-        configureFlags+=" --extra-include-dirs=$p/include"
-      fi
-      if [ -d "$p/lib" ]; then
-        configureFlags+=" --extra-lib-dirs=$p/lib"
-      fi
+      ${buildPkgDb ghc.name}
     done
   ''
   # only use the links hack if we're actually building dylibs. otherwise, the
   # "dynamic-library-dirs" point to nonexistent paths, and the ln command becomes
   # "ln -s $out/lib/links", which tries to recreate the links dir and fails
-  + (optionalString (stdenv.isDarwin && enableSharedLibraries) ''
+  + (optionalString (stdenv.isDarwin && (enableSharedLibraries || enableSharedExecutables)) ''
     # Work around a limit in the macOS Sierra linker on the number of paths
     # referenced by any one dynamic library:
     #
···
     done
 
     echo setupCompileFlags: $setupCompileFlags
-    ${nativeGhcCommand} $setupCompileFlags --make -o Setup -odir $TMPDIR -hidir $TMPDIR $i
+    ${optionalString (setupHaskellDepends != [])
+       ''
+       echo GHC_PACKAGE_PATH="$setupPackageConfDir:"
+       GHC_PACKAGE_PATH="$setupPackageConfDir:" ''
+    }${nativeGhcCommand} $setupCompileFlags --make -o Setup -odir $TMPDIR -hidir $TMPDIR $i
 
     runHook postCompileBuildDriver
   '';
···
 
   buildPhase = ''
     runHook preBuild
-    ${setupCommand} build ${buildTarget}${crossCabalFlagsString}
+    ${setupCommand} build ${buildTarget}${crossCabalFlagsString}${buildFlagsString}
     runHook postBuild
   '';
 

pkgs/development/haskell-modules/lib.nix

···
    */
   appendConfigureFlag = drv: x: overrideCabal drv (drv: { configureFlags = (drv.configureFlags or []) ++ [x]; });
 
+  appendBuildFlag = drv: x: overrideCabal drv (drv: { buildFlags = (drv.buildFlags or []) ++ [x]; });
+  appendBuildFlags = drv: xs: overrideCabal drv (drv: { buildFlags = (drv.buildFlags or []) ++ xs; });
   /* removeConfigureFlag drv x is a Haskell package like drv, but with
      all cabal configure arguments that are equal to x removed.