python2: copy stub library to output on cygwin

pkgs/development/interpreters/python/cpython/2.7/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchurl
+{ stdenv, hostPlatform, fetchurl
 , bzip2
 , gdbm
 , fetchpatch
@@ -69,7 +69,7 @@ let
 
       ./glibc-2.25-enosys.patch
 
-    ] ++ optionals stdenv.isCygwin [
+    ] ++ optionals hostPlatform.isCygwin [
       ./2.5.2-ctypes-util-find_library.patch
       ./2.5.2-tkinter-x11.patch
       ./2.6.2-ssl-threads.patch
@@ -110,7 +110,7 @@ let
     "--enable-shared"
     "--with-threads"
     "--enable-unicode=ucs4"
-  ] ++ optionals stdenv.isCygwin [
+  ] ++ optionals hostPlatform.isCygwin [
     "--with-system-ffi"
     "--with-system-expat"
     "ac_cv_func_bind_textdomain_codeset=yes"
@@ -118,14 +118,14 @@ let
     "--disable-toolbox-glue"
   ];
 
-  postConfigure = if stdenv.isCygwin then ''
+  postConfigure = if hostPlatform.isCygwin then ''
     sed -i Makefile -e 's,PYTHONPATH="$(srcdir),PYTHONPATH="$(abs_srcdir),'
   '' else null;
 
   buildInputs =
     optional (stdenv ? cc && stdenv.cc.libc != null) stdenv.cc.libc ++
     [ bzip2 openssl zlib ]
-    ++ optionals stdenv.isCygwin [ expat libffi ]
+    ++ optionals hostPlatform.isCygwin [ expat libffi ]
     ++ [ db gdbm ncurses sqlite readline ]
     ++ optionals x11Support [ tcl tk xlibsWrapper libX11 ]
     ++ optionals stdenv.isDarwin [ CF configd ];
@@ -190,6 +190,8 @@ in stdenv.mkDerivation {
         find $out -name "*.py" | $out/bin/python -m compileall -q -f -x "lib2to3" -i -
         find $out -name "*.py" | $out/bin/python -O -m compileall -q -f -x "lib2to3" -i -
         find $out -name "*.py" | $out/bin/python -OO -m compileall -q -f -x "lib2to3" -i -
+      '' + optionalString hostPlatform.isCygwin ''
+        cp libpython2.7.dll.a $out/lib
       '';
 
     passthru = let