diff -urNd gdal-2.3.1/port/cpl_vsil_curl.cpp gdal-2.3.1-curl/port/cpl_vsil_curl.cpp
--- gdal-2.3.1/port/cpl_vsil_curl.cpp	2018-06-24 01:10:23.000000000 +1000
+++ gdal-2.3.1-curl/port/cpl_vsil_curl.cpp	2018-07-13 01:29:31.326347717 +1000
@@ -8617,8 +8617,10 @@
         if( poFSHandler )
             poFSHandler->ClearCache();
     }
-
+#if !defined(HAVE_CURL) || defined(CPL_MULTIPROC_STUB)
+#else
     VSICurlStreamingClearCache();
+#endif
 }
 
 #endif /* HAVE_CURL */