cross: Allow Windows toolchains to use ucrt as libc.

pkgs/development/compilers/gcc/10/default.nix

@@ -79,7 +79,7 @@ let majorVersion = "10";
       });
 
     /* Cross-gcc settings (build == host != target) */
-    crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
+    crossMingw = targetPlatform != hostPlatform && targetPlatform.isMinGW;
     stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
@@ -292,7 +292,7 @@ stdenv.mkDerivation ({
   };
 }
 
-// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt" && crossStageStatic) {
+// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.isMinGW && crossStageStatic) {
   makeFlags = [ "all-gcc" "all-target-libgcc" ];
   installTargets = "install-gcc install-target-libgcc";
 }

pkgs/development/compilers/gcc/11/default.nix

@@ -82,7 +82,7 @@ let majorVersion = "11";
       ++ optional (!crossStageStatic && targetPlatform.isMinGW) ./Added-mcf-thread-model-support-from-mcfgthread.patch;
 
     /* Cross-gcc settings (build == host != target) */
-    crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
+    crossMingw = targetPlatform != hostPlatform && targetPlatform.isMinGW;
     stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
@@ -296,7 +296,7 @@ stdenv.mkDerivation ({
   };
 }
 
-// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt" && crossStageStatic) {
+// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.isMinGW && crossStageStatic) {
   makeFlags = [ "all-gcc" "all-target-libgcc" ];
   installTargets = "install-gcc install-target-libgcc";
 }

pkgs/development/compilers/gcc/4.8/default.nix

@@ -114,7 +114,7 @@ let majorVersion = "4";
     javaAwtGtk = langJava && x11Support;
 
     /* Cross-gcc settings (build == host != target) */
-    crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
+    crossMingw = targetPlatform != hostPlatform && targetPlatform.isMinGW;
     stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
@@ -316,7 +316,7 @@ stdenv.mkDerivation ({
   };
 }
 
-// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt" && crossStageStatic) {
+// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.isMinGW && crossStageStatic) {
   makeFlags = [ "all-gcc" "all-target-libgcc" ];
   installTargets = "install-gcc install-target-libgcc";
 }

pkgs/development/compilers/gcc/4.9/default.nix

@@ -130,7 +130,7 @@ let majorVersion = "4";
     javaAwtGtk = langJava && x11Support;
 
     /* Cross-gcc settings (build == host != target) */
-    crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
+    crossMingw = targetPlatform != hostPlatform && targetPlatform.isMinGW;
     stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
@@ -332,7 +332,7 @@ stdenv.mkDerivation ({
   };
 }
 
-// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt" && crossStageStatic) {
+// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.isMinGW && crossStageStatic) {
   makeFlags = [ "all-gcc" "all-target-libgcc" ];
   installTargets = "install-gcc install-target-libgcc";
 }

pkgs/development/compilers/gcc/6/default.nix

@@ -111,7 +111,7 @@ let majorVersion = "6";
     javaAwtGtk = langJava && x11Support;
 
     /* Cross-gcc settings (build == host != target) */
-    crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
+    crossMingw = targetPlatform != hostPlatform && targetPlatform.isMinGW;
     stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
@@ -345,7 +345,7 @@ stdenv.mkDerivation ({
   };
 }
 
-// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt" && crossStageStatic) {
+// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.isMinGW && crossStageStatic) {
   makeFlags = [ "all-gcc" "all-target-libgcc" ];
   installTargets = "install-gcc install-target-libgcc";
 }

pkgs/development/compilers/gcc/7/default.nix

@@ -87,7 +87,7 @@ let majorVersion = "7";
       ++ [ ../libsanitizer-no-cyclades-9.patch ];
 
     /* Cross-gcc settings (build == host != target) */
-    crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
+    crossMingw = targetPlatform != hostPlatform && targetPlatform.isMinGW;
     stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
@@ -301,7 +301,7 @@ stdenv.mkDerivation ({
   };
 }
 
-// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt" && crossStageStatic) {
+// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.isMinGW && crossStageStatic) {
   makeFlags = [ "all-gcc" "all-target-libgcc" ];
   installTargets = "install-gcc install-target-libgcc";
 }

pkgs/development/compilers/gcc/8/default.nix

@@ -71,7 +71,7 @@ let majorVersion = "8";
       ++ [ ../libsanitizer-no-cyclades-9.patch ];
 
     /* Cross-gcc settings (build == host != target) */
-    crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
+    crossMingw = targetPlatform != hostPlatform && targetPlatform.isMinGW;
     stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
@@ -280,7 +280,7 @@ stdenv.mkDerivation ({
   };
 }
 
-// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt" && crossStageStatic) {
+// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.isMinGW && crossStageStatic) {
   makeFlags = [ "all-gcc" "all-target-libgcc" ];
   installTargets = "install-gcc install-target-libgcc";
 }

pkgs/development/compilers/gcc/9/default.nix

@@ -98,7 +98,7 @@ let majorVersion = "9";
       ++ [ ../libsanitizer-no-cyclades-9.patch ];
 
     /* Cross-gcc settings (build == host != target) */
-    crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
+    crossMingw = targetPlatform != hostPlatform && targetPlatform.isMinGW;
     stageNameAddon = if crossStageStatic then "stage-static" else "stage-final";
     crossNameAddon = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-${stageNameAddon}-";
 
@@ -311,7 +311,7 @@ stdenv.mkDerivation ({
   };
 }
 
-// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt" && crossStageStatic) {
+// optionalAttrs (targetPlatform != hostPlatform && targetPlatform.isMinGW && crossStageStatic) {
   makeFlags = [ "all-gcc" "all-target-libgcc" ];
   installTargets = "install-gcc install-target-libgcc";
 }

pkgs/development/compilers/gcc/common/configure-flags.nix

@@ -41,7 +41,7 @@ let
   inherit (stdenv)
     buildPlatform hostPlatform targetPlatform;
 
-  crossMingw = targetPlatform != hostPlatform && targetPlatform.libc == "msvcrt";
+  crossMingw = targetPlatform != hostPlatform && targetPlatform.isMinGW;
   crossDarwin = targetPlatform != hostPlatform && targetPlatform.libc == "libSystem";
 
   targetPrefix = lib.optionalString (stdenv.targetPlatform != stdenv.hostPlatform)

pkgs/development/libraries/boost/generic.nix

@@ -9,7 +9,7 @@
 , enableDebug ? false
 , enableSingleThreaded ? false
 , enableMultiThreaded ? true
-, enableShared ? !(with stdenv.hostPlatform; isStatic || libc == "msvcrt") # problems for now
+, enableShared ? !(with stdenv.hostPlatform; isStatic || isMinGW) # problems for now
 , enableStatic ? !enableShared
 , enablePython ? false
 , enableNumpy ? false
@@ -102,7 +102,7 @@ let
     ++ optional (toolset != null) "toolset=${toolset}"
     ++ optional (!enablePython) "--without-python"
     ++ optional needUserConfig "--user-config=user-config.jam"
-    ++ optionals (stdenv.hostPlatform.libc == "msvcrt") [
+    ++ optionals (stdenv.hostPlatform.isMinGW) [
     "threadapi=win32"
   ] ++ extraB2Args
   );
@@ -252,7 +252,7 @@ stdenv.mkDerivation {
     # Make boost header paths relative so that they are not runtime dependencies
     cd "$dev" && find include \( -name '*.hpp' -or -name '*.h' -or -name '*.ipp' \) \
       -exec sed '1s/^\xef\xbb\xbf//;1i#line 1 "{}"' -i '{}' \;
-  '' + optionalString (stdenv.hostPlatform.libc == "msvcrt") ''
+  '' + optionalString (stdenv.hostPlatform.isMinGW) ''
     $RANLIB "$out/lib/"*.a
   '';
 

pkgs/development/libraries/libiconv/default.nix

@@ -20,7 +20,7 @@ stdenv.mkDerivation rec {
   ];
 
   postPatch =
-    lib.optionalString ((stdenv.hostPlatform != stdenv.buildPlatform && stdenv.hostPlatform.libc == "msvcrt") || stdenv.cc.nativeLibc)
+    lib.optionalString ((stdenv.hostPlatform != stdenv.buildPlatform && stdenv.hostPlatform.isMinGW) || stdenv.cc.nativeLibc)
       ''
         sed '/^_GL_WARN_ON_USE (gets/d' -i srclib/stdio.in.h
       ''

pkgs/development/libraries/libjpeg-turbo/default.nix

@@ -27,7 +27,7 @@ stdenv.mkDerivation rec {
 
   # This is needed by freeimage
   patches = [ ./0001-Compile-transupp.c-as-part-of-the-library.patch ]
-    ++ lib.optional (stdenv.hostPlatform.libc or null == "msvcrt")
+    ++ lib.optional (stdenv.hostPlatform.isMinGW)
     ./mingw-boolean.patch;
 
   outputs = [ "bin" "dev" "dev_private" "out" "man" "doc" ];

pkgs/development/libraries/libxml2/default.nix

@@ -14,7 +14,7 @@
 , pythonSupport ? enableShared && stdenv.buildPlatform == stdenv.hostPlatform
 , icuSupport ? false
 , icu
-, enableShared ? stdenv.hostPlatform.libc != "msvcrt" && !stdenv.hostPlatform.isStatic
+, enableShared ? !stdenv.hostPlatform.isMinGW && !stdenv.hostPlatform.isStatic
 , enableStatic ? !enableShared
 , gnome
 }:

pkgs/development/libraries/zlib/default.nix

@@ -88,7 +88,7 @@ stdenv.mkDerivation (rec {
   ''
     # Non-typical naming confuses libtool which then refuses to use zlib's DLL
     # in some cases, e.g. when compiling libpng.
-  + lib.optionalString (stdenv.hostPlatform.libc == "msvcrt" && shared) ''
+  + lib.optionalString (stdenv.hostPlatform.isMinGW && shared) ''
     ln -s zlib1.dll $out/bin/libz.dll
   '';
 
@@ -101,7 +101,7 @@ stdenv.mkDerivation (rec {
   dontStrip = stdenv.hostPlatform != stdenv.buildPlatform && static;
   configurePlatforms = [];
 
-  installFlags = lib.optionals (stdenv.hostPlatform.libc == "msvcrt") [
+  installFlags = lib.optionals (stdenv.hostPlatform.isMinGW) [
     "BINARY_PATH=$(out)/bin"
     "INCLUDE_PATH=$(dev)/include"
     "LIBRARY_PATH=$(out)/lib"
@@ -112,7 +112,7 @@ stdenv.mkDerivation (rec {
 
   makeFlags = [
     "PREFIX=${stdenv.cc.targetPrefix}"
-  ] ++ lib.optionals (stdenv.hostPlatform.libc == "msvcrt") [
+  ] ++ lib.optionals (stdenv.hostPlatform.isMinGW) [
     "-f" "win32/Makefile.gcc"
   ] ++ lib.optionals shared [
     # Note that as of writing (zlib 1.2.11), this flag only has an effect
@@ -134,6 +134,6 @@ stdenv.mkDerivation (rec {
   preConfigure = ''
     export CHOST=${stdenv.hostPlatform.config}
   '';
-} // lib.optionalAttrs (stdenv.hostPlatform.libc == "msvcrt") {
+} // lib.optionalAttrs (stdenv.hostPlatform.isMinGW) {
   dontConfigure = true;
 })

pkgs/os-specific/windows/mingw-w64/default.nix

@@ -19,6 +19,7 @@ let
     then [] # maybe autoconf will save us
     else map (arch: lib.enableFeature (arch == enabledArch) "lib${arch}") knownArches;
 
+  crt = stdenv.hostPlatform.libc;
 in stdenv.mkDerivation {
   pname = "mingw-w64";
   inherit version;
@@ -33,6 +34,7 @@ in stdenv.mkDerivation {
   configureFlags = [
     "--enable-idl"
     "--enable-secure-api"
+    "--with-default-msvcrt=${crt}"
   ] ++ archFlags;
 
   enableParallelBuilding = true;
@@ -43,5 +45,6 @@ in stdenv.mkDerivation {
 
   meta = {
     platforms = lib.platforms.windows;
+    broken = !(lib.elem crt [ "msvcrt" "ucrt" ]);
   };
 }

pkgs/os-specific/windows/mingw-w64/headers.nix

@@ -1,6 +1,8 @@
 { stdenvNoCC, mingw_w64 }:
 
-stdenvNoCC.mkDerivation {
+let
+  crt = stdenvNoCC.hostPlatform.libc;
+in stdenvNoCC.mkDerivation {
   name = "${mingw_w64.name}-headers";
   inherit (mingw_w64) src meta;
 
@@ -8,4 +10,10 @@ stdenvNoCC.mkDerivation {
     cd mingw-w64-headers
   '';
 
+  configureFlags = [
+    "--enable-idl"
+    "--enable-secure-api"
+    "--with-default-msvcrt=${crt}"
+  ];
+
 }

pkgs/top-level/all-packages.nix

@@ -17415,7 +17415,7 @@ with pkgs;
   # These are used when buiding compiler-rt / libgcc, prior to building libc.
   preLibcCrossHeaders = let
     inherit (stdenv.targetPlatform) libc;
-  in     if libc == "msvcrt" then targetPackages.windows.mingw_w64_headers or windows.mingw_w64_headers
+  in     if libc == "msvcrt" || libc == "ucrt" then targetPackages.windows.mingw_w64_headers or windows.mingw_w64_headers
     else if libc == "nblibc" then targetPackages.netbsdCross.headers or netbsdCross.headers
     else if libc == "libSystem" && stdenv.targetPlatform.isAarch64 then targetPackages.darwin.LibsystemCross or darwin.LibsystemCross
     else null;
@@ -17434,7 +17434,7 @@ with pkgs;
     else if name == "newlib" then targetPackages.newlibCross or newlibCross
     else if name == "newlib-nano" then targetPackages.newlib-nanoCross or newlib-nanoCross
     else if name == "musl" then targetPackages.muslCross or muslCross
-    else if name == "msvcrt" then targetPackages.windows.mingw_w64 or windows.mingw_w64
+    else if name == "msvcrt" || name == "ucrt" then targetPackages.windows.mingw_w64 or windows.mingw_w64
     else if name == "libSystem" then
       if stdenv.targetPlatform.useiOSPrebuilt
       then targetPackages.darwin.iosSdkPkgs.libraries or darwin.iosSdkPkgs.libraries