diff -ru -x '*o' graphviz-2.30.1.orig/tclpkg/gv/gv_php_init.c graphviz-2.30.1/tclpkg/gv/gv_php_init.c
--- graphviz-2.30.1.orig/tclpkg/gv/gv_php_init.c	2013-02-27 12:25:47.939799924 +0100
+++ graphviz-2.30.1/tclpkg/gv/gv_php_init.c	2013-02-27 12:26:41.890065699 +0100
@@ -19,11 +19,13 @@
 
 static size_t gv_string_writer (GVJ_t *job, const char *s, size_t len)
 {
+    TSRMLS_FETCH();
     return PHPWRITE(s, len);
 }
 
 static size_t gv_channel_writer (GVJ_t *job, const char *s, size_t len)
 {
+    TSRMLS_FETCH();
     return PHPWRITE(s, len);
 }