Properly escape preprocessor directives

Otherwise swig will process them instead of the compiler

Should have been in commit 170f855

Author: mlschroe

bindings/solv.i

@@ -44,11 +44,11 @@ typedef struct {
 #if defined(SWIGPYTHON)
     const void *pybuf = 0;
     Py_ssize_t pysize = 0;
-#if PY_VERSION_HEX >= 0x03000000
-    res = PyBytes_AsStringAndSize($input, &pybuf, &pysize);
-#else
+%#if PY_VERSION_HEX >= 0x03000000
+    res = PyBytes_AsStringAndSize($input, (char **)&pybuf, &pysize);
+%#else
     res = PyObject_AsReadBuffer($input, &pybuf, &pysize);
-#endif
+%#endif
     if (res < 0) {
       %argument_fail(res, "BinaryBlob", $symname, $argnum);
     } else {