Detect infinite recursion in parameter entities

When expanding a parameter entity in a DTD, infinite recursion could
lead to an infinite loop or memory exhaustion.

Thanks to Wei Lei for the first of many reports.

Fixes bug 759579.

1 files changed, 7 insertions, 0 deletions

diff --git a/result/errors/759579.xml.str b/result/errors/759579.xml.str
new file mode 100644
index 00000000..09408f52
--- /dev/null
+++ b/result/errors/759579.xml.str
@@ -0,0 +1,7 @@
+Entity: line 2: parser error : Detected an entity reference loop
+        %z; %z; %z; %z; %z;
+           ^
+Entity: line 2: 
+        %z; %z; %z; %z; %z;
+           ^
+./test/errors/759579.xml : failed to parse