msp430: include vendor headers with stdenv

lib/systems/default.nix

···
         else if final.isUClibc              then "uclibc"
         else if final.isAndroid             then "bionic"
         else if final.isLinux /* default */ then "glibc"
+        else if final.isMsp430              then "newlib"
         else if final.isAvr                 then "avrlibc"
         # TODO(@Ericson2314) think more about other operating systems
         else                                     "native/impure";

pkgs/development/misc/msp430/newlib.nix

···
+{ runCommand, lndir, newlib, msp430GccSupport }:
+
+runCommand "msp430-${newlib.name}" {
+  inherit newlib;
+  inherit msp430GccSupport;
+
+  preferLocalBuild = true;
+  allowSubstitutes = false;
+
+  passthru = {
+    inherit (newlib) incdir libdir;
+  };
+} ''
+  mkdir $out
+  ${lndir}/bin/lndir -silent $newlib $out
+  ${lndir}/bin/lndir -silent $msp430GccSupport/include $out/${newlib.incdir}
+  ${lndir}/bin/lndir -silent $msp430GccSupport/lib $out/${newlib.libdir}
+''

pkgs/top-level/all-packages.nix

···
 
   msp430GccSupport = callPackage ../development/misc/msp430/gcc-support.nix { };
 
+  msp430Newlib      = callPackage ../development/misc/msp430/newlib.nix { };
+  msp430NewlibCross = callPackage ../development/misc/msp430/newlib.nix {
+    inherit (pkgs.buildPackages.xorg) lndir;
+    newlib = pkgs.newlibCross;
+  };
+
   pharo-vms = callPackage ../development/pharo/vm { };
   pharo = pharo-vms.multi-vm-wrapper;
   pharo-cog32 = pharo-vms.cog32;
···
     else if name == "bionic" then targetPackages.bionic or bionic
     else if name == "uclibc" then targetPackages.uclibcCross or uclibcCross
     else if name == "avrlibc" then targetPackages.avrlibcCross or avrlibcCross
+    else if name == "newlib" && stdenv.targetPlatform.isMsp430 then targetPackages.msp430NewlibCross or msp430NewlibCross
     else if name == "newlib" then targetPackages.newlibCross or newlibCross
     else if name == "musl" then targetPackages.muslCross or muslCross
     else if name == "msvcrt" then targetPackages.windows.mingw_w64 or windows.mingw_w64