kermit: fix build

... by explicitly selecting the Linux code paths in the source.

pkgs/tools/misc/kermit/default.nix

@@ -21,7 +21,7 @@ stdenv.mkDerivation {
       -e 's@/usr/local@'"$out"@ makefile
   '';
 
-  buildPhase = "make -f makefile linux LNKFLAGS='-lcrypt -lresolv'";
+  buildPhase = "make -f makefile linux KFLAGS='-D_IO_file_flags' LNKFLAGS='-lcrypt -lresolv'";
 
   installPhase = ''
     mkdir -p $out/bin
@@ -35,6 +35,5 @@ stdenv.mkDerivation {
     license = licenses.bsd3;
     maintainers = with maintainers; [ pSub ];
     platforms = with platforms; linux;
-    broken = true;
   };
 }