python: fix build problems with Cython 0.20

Resolve the following build problem with Cython 0.20; I've also tested
this change on Cython 0.19.2 without problem.

>>>
Error compiling Cython file:
------------------------------------------------------------
...
        Helper function which should only be used internally by
        SyscallFilter objects and exists for the sole purpose of making it
        easier to deal with the varadic functions of the libseccomp API,
        e.g. seccomp_rule_add().
        """
        return self._arg
                  ^
------------------------------------------------------------

seccomp.pyx:194:19: Cannot convert 'scmp_arg_cmp' to Python object
>>>

Signed-off-by: Paul Moore <pmoore@redhat.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/src/python/seccomp.pyx b/src/python/seccomp.pyx
index 01ea0a9..4082bad 100644
--- a/src/python/seccomp.pyx
+++ b/src/python/seccomp.pyx
@@ -182,7 +182,7 @@ cdef class Arg:
         self._arg.datum_a = datum_a
         self._arg.datum_b = datum_b
 
-    def to_c(self):
+    cdef libseccomp.scmp_arg_cmp to_c(self):
         """ Convert the object into a C structure.
 
         Description:
@@ -425,6 +425,7 @@ cdef class SyscallFilter:
         """ NOTE: the code below exists solely to deal with the varadic
         nature of seccomp_rule_add() function and the inability of Cython
         to handle this automatically """
+        cdef Arg arg
         for i, arg in enumerate(args):
             c_arg[i] = arg.to_c()
         if len(args) == 0:
@@ -504,6 +505,7 @@ cdef class SyscallFilter:
         """ NOTE: the code below exists solely to deal with the varadic
         nature of seccomp_rule_add_exact() function and the inability of
         Cython to handle this automatically """
+        cdef Arg arg
         for i, arg in enumerate(args):
             c_arg[i] = arg.to_c()
         if len(args) == 0: