python: Renaming and fixing 'generic' build

Signed-off-by: David Shah <davey1576@gmail.com>

common/pywrappers.h

@@ -221,7 +221,6 @@ template <typename Class, typename FuncT, FuncT fn> struct fn_wrapper_0a_v
 
     static void wrapped_fn(class_type &cls)
     {
-        Context *ctx = get_ctx<Class>(cls);
         Class &base = get_base<Class>(cls);
         return (base.*fn)();
     }

generic/arch_pybindings.h

@@ -0,0 +1,31 @@
+/*
+ *  nextpnr -- Next Generation Place and Route
+ *
+ *  Copyright (C) 2018  Clifford Wolf <clifford@symbioticeda.com>
+ *  Copyright (C) 2018  David Shah <david@symbioticeda.com>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+#ifndef ARCH_PYBINDINGS_H
+#define ARCH_PYBINDINGS_H
+#ifndef NO_PYTHON
+
+#include "pybindings.h"
+#include "nextpnr.h"
+
+NEXTPNR_NAMESPACE_BEGIN
+
+NEXTPNR_NAMESPACE_END
+#endif
+#endif