Fix silly mistake.

Thanks Antony :)

main/streams/filter.c

@@ -283,7 +283,7 @@ PHPAPI void php_stream_filter_free(php_stream_filter *filter TSRMLS_DC)
 	pefree(filter, filter->is_persistent);
 }
 
-PHPAPI void php_stream_filter_prepend(php_stream_filter_chain *chain, php_stream_filter *filter TSRMLS_DC)
+PHPAPI void _php_stream_filter_prepend(php_stream_filter_chain *chain, php_stream_filter *filter TSRMLS_DC)
 {
 	filter->next = chain->head;
 	filter->prev = NULL;
@@ -297,7 +297,7 @@ PHPAPI void php_stream_filter_prepend(php_stream_filter_chain *chain, php_stream
 	filter->chain = chain;
 }
 
-PHPAPI void php_stream_filter_append(php_stream_filter_chain *chain, php_stream_filter *filter TSRMLS_DC)
+PHPAPI void _php_stream_filter_append(php_stream_filter_chain *chain, php_stream_filter *filter TSRMLS_DC)
 {
 	php_stream *stream = chain->stream;
 

main/streams/php_stream_filter_api.h

@@ -129,8 +129,8 @@ PHPAPI php_stream_filter *_php_stream_filter_alloc(php_stream_filter_ops *fops,
 END_EXTERN_C()
 #define php_stream_filter_alloc(fops, thisptr, persistent) _php_stream_filter_alloc((fops), (thisptr), (persistent) STREAMS_CC TSRMLS_CC)
 #define php_stream_filter_alloc_rel(fops, thisptr, persistent) _php_stream_filter_alloc((fops), (thisptr), (persistent) STREAMS_REL_CC TSRMLS_CC)
-#define php_stream_fitler_prepend(chain, filter) _php_stream_filter_prepend((chain), (filter) TSRMLS_CC)
-#define php_stream_fitler_append(chain, filter) _php_stream_filter_append((chain), (filter) TSRMLS_CC)
+#define php_stream_filter_prepend(chain, filter) _php_stream_filter_prepend((chain), (filter) TSRMLS_CC)
+#define php_stream_filter_append(chain, filter) _php_stream_filter_append((chain), (filter) TSRMLS_CC)
 
 #define php_stream_is_filtered(stream)	((stream)->readfilters.head || (stream)->writefilters.head)