Move some common code from if_python.c and if_python3.c to if_py_both.h.
diff --git a/Filelist b/Filelist
index ea6d780..4bcaccc 100644
--- a/Filelist
+++ b/Filelist
@@ -217,6 +217,7 @@
 		src/if_perlsfio.c \
 		src/if_python.c \
 		src/if_python3.c \
+		src/if_py_both.h \
 		src/if_ruby.c \
 		src/if_sniff.h \
 		src/if_tcl.c \