redox: add as target

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

@@ -64,9 +64,9 @@ let majorVersion = "6";
 
     inherit (stdenv) buildPlatform hostPlatform targetPlatform;
 
-    patches =
-      [ ../use-source-date-epoch.patch ./0001-Fix-build-for-glibc-2.31.patch ]
-      ++ optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
+    patches = optionals (!stdenv.targetPlatform.isRedox) [
+      ../use-source-date-epoch.patch ./0001-Fix-build-for-glibc-2.31.patch
+    ] ++ optional (targetPlatform != hostPlatform) ../libstdc++-target.patch
       ++ optional noSysDirs ../no-sys-dirs.patch
       ++ optional langAda ../gnat-cflags.patch
       ++ optional langFortran ../gfortran-driving.patch
@@ -120,6 +120,11 @@ stdenv.mkDerivation ({
     repo = "gcc-vc4";
     rev = "e90ff43f9671c760cf0d1dd62f569a0fb9bf8918";
     sha256 = "0gxf66hwqk26h8f853sybphqa5ca0cva2kmrw5jsiv6139g0qnp8";
+  } else if stdenv.targetPlatform.isRedox then fetchFromGitHub {
+    owner = "redox-os";
+    repo = "gcc";
+    rev = "f360ac095028d286fc6dde4d02daed48f59813fa"; # `redox` branch
+    sha256 = "1an96h8l58pppyh3qqv90g8hgcfd9hj7igvh2gigmkxbrx94khfl";
   } else fetchurl {
     url = "mirror://gnu/gcc/gcc-${version}/gcc-${version}.tar.xz";
     sha256 = "0i89fksfp6wr1xg9l8296aslcymv2idn60ip31wr9s4pwin7kwby";
@@ -182,7 +187,7 @@ stdenv.mkDerivation ({
   nativeBuildInputs = [ texinfo which gettext ]
     ++ (optional (perl != null) perl)
     ++ (optional javaAwtGtk pkgconfig)
-    ++ (optional (stdenv.targetPlatform.isVc4) flex);
+    ++ (optional (with stdenv.targetPlatform; isVc4 || isRedox) flex);
 
   # For building runtime libs
   depsBuildTarget =