Add more entries to the glossary.

Written by Jeff Wheeler for GHOP.
diff --git a/Doc/README.txt b/Doc/README.txt
index 9959da2..6e135e9 100644
--- a/Doc/README.txt
+++ b/Doc/README.txt
@@ -48,6 +48,9 @@
    To create the CHM file, you need to run the Microsoft HTML Help Workshop
    over the generated project (.hhp) file.
 
+ * "latex", which builds LaTeX source files that can be run with "pdflatex"
+   to produce PDF documents.
+
 A "make update" updates the Subversion checkouts in `tools/`.