diff -urN calibre-2.33.0/setup/extensions.py calibre-2.33.0-patched/setup/extensions.py
--- calibre-2.33.0/setup/extensions.py	2015-07-24 13:40:19.000000000 +1000
+++ calibre-2.33.0-patched/setup/extensions.py	2015-08-01 00:30:50.642494253 +1000
@@ -609,6 +609,9 @@
         macx {{
             QMAKE_LFLAGS += "-undefined dynamic_lookup"
         }}
+        unix {{
+            LIBS += "-lpython2.7"
+        }}
         ''').format(
             target=sip['target'], headers=' '.join(sip['headers'] + ext.headers), sources=' '.join(ext.sources + sip['sources']),
             sipinc=pyqt['sip_inc_dir'], pyinc=sysconfig.get_python_inc(), py_lib=py_lib,