diff --git a/chapter08/glibc.xml b/chapter08/glibc.xml
index ec81b2da7..ff655a89e 100644
--- a/chapter08/glibc.xml
+++ b/chapter08/glibc.xml
@@ -50,8 +50,12 @@
 
 <screen><userinput remap="pre">patch -Np1 -i ../&glibc-fhs-patch;</userinput></screen>
 
-    <!-- https://sourceware.org/bugzilla/show_bug.cgi?id=30068 -->
-    <para>Fix an issue identified upstream:</para>
+    <!-- https://sourceware.org/bugzilla/show_bug.cgi?id=30068
+         Upstream fix also added a test case and renamed "prec" to
+         "prec_inc".  We'll test this with MPFR test suite so we don't
+         need the test here, and the renaming does not affect program
+         behavior.  -->
+    <para>Fix a security issue identified upstream:</para>
 
 <screen><userinput remap="pre">sed '/width -=/s/workend - string/number_length/' \
     -i stdio-common/vfprintf-process-arg.c</userinput></screen>