Use ZLIB_RUNTIME_VERSION if available

Author: otethal

Diff for: gitdb/stream.py

@@ -294,7 +294,7 @@ def read(self, size=-1):
         # However, the zlib VERSIONs as well as the platform check is used to further match the entries in the 
         # table in the github issue. This is it ... it was the only way I could make this work everywhere.
         # IT's CERTAINLY GOING TO BITE US IN THE FUTURE ... .
-        if zlib.ZLIB_VERSION in ('1.2.7', '1.2.5') and not sys.platform == 'darwin':
+        if getattr(zlib, 'ZLIB_RUNTIME_VERSION', zlib.ZLIB_VERSION) in ('1.2.7', '1.2.5') and not sys.platform == 'darwin':
             unused_datalen = len(self._zip.unconsumed_tail)
         else:
             unused_datalen = len(self._zip.unconsumed_tail) + len(self._zip.unused_data)