Don't build CLooG-PPL on Cygwin.

svn path=/nixpkgs/trunk/; revision=17221

pkgs/development/libraries/cloog-ppl/default.nix

@@ -37,5 +37,26 @@ stdenv.mkDerivation rec {
     license = "GPLv2+";
 
     maintainers = [ stdenv.lib.maintainers.ludo ];
+
+    /* Leads to an ICE on Cygwin:
+
+       make[3]: Entering directory `/tmp/nix-build-9q5gw5m37q5l4f0kjfv9ar8fsc9plk27-ppl-0.10.2.drv-1/ppl-0.10.2/src'
+       /bin/sh ../libtool --tag=CXX   --mode=compile g++ -DHAVE_CONFIG_H -I. -I..  -I.. -I../src    -g -O2 -frounding-math  -W -Wall -c -o Box.lo Box.cc
+       libtool: compile:  g++ -DHAVE_CONFIG_H -I. -I.. -I.. -I../src -g -O2 -frounding-math -W -Wall -c Box.cc  -DDLL_EXPORT -DPIC -o .libs/Box.o
+       In file included from checked.defs.hh:595,
+                        from Checked_Number.defs.hh:27,
+                        from Coefficient.types.hh:15,
+                        from Coefficient.defs.hh:26,
+                        from Box.defs.hh:28,
+                        from Box.cc:24:
+       checked.inlines.hh: In function `Parma_Polyhedra_Library::Result Parma_Polyhedra_Library::Checked::input_generic(Type&, std::istream&, Parma_Polyhedra_Library::Rounding_Dir)':
+       checked.inlines.hh:607: internal compiler error: in invert_truthvalue, at fold-const.c:2719
+       Please submit a full bug report,
+       with preprocessed source if appropriate.
+       See <URL:http://cygwin.com/problems.html> for instructions.
+       make[3]: *** [Box.lo] Error 1
+
+    */
+    platforms = stdenv.lib.allBut "i686-cygwin";
   };
 }