ncurses: fix cygwin build

pkgs/development/libraries/ncurses/default.nix

@@ -61,8 +61,6 @@ stdenv.mkDerivation rec {
            -e '/CPPFLAGS="$CPPFLAGS/s/ -D_XOPEN_SOURCE_EXTENDED//' \
         configure
     CFLAGS=-D_XOPEN_SOURCE_EXTENDED
-  '' + lib.optionalString stdenv.isCygwin ''
-    sed -i -e 's,LIB_SUFFIX="t,LIB_SUFFIX=",' configure
   '';
 
   enableParallelBuilding = true;
@@ -122,7 +120,7 @@ stdenv.mkDerivation rec {
     moveToOutput "bin/tset" "$out"
   '';
 
-  preFixup = ''
+  preFixup = lib.optionalString (!hostPlatform.isCygwin) ''
     rm "$out"/lib/*.a
   '';