setup: Add build dependency information

Manaully, because there is no automatic dependency tracking in
setuptools...

Dependency tracking is needed to avoid miscompilation after incremental
update under SlapOS/buildout/testnode/... when e.g. only .h was changed.

setup.py

@@ -273,6 +273,19 @@ setup(
                          'bigfile/virtmem.c',
                          'lib/bug.c',
                          'lib/utils.c'],
+                        depends = [
+                         'bigfile/_bigfile.h',
+                         'include/wendelin/compat_py2.h',
+                         '3rdparty/include/linux/list.h',
+                         'include/wendelin/bigfile/file.h',
+                         'include/wendelin/bigfile/pagemap.h',
+                         'include/wendelin/bigfile/ram.h',
+                         'include/wendelin/bigfile/types.h',
+                         'include/wendelin/bigfile/virtmem.h',
+                         'include/wendelin/bug.h',
+                         'include/wendelin/list.h',
+                         'include/wendelin/utils.h',
+                        ],
                         define_macros   = [('_GNU_SOURCE',None)],
                         language        = 'c'),
                   ],