Added \platform annotations.
diff --git a/Doc/lib/libcd.tex b/Doc/lib/libcd.tex
index 9c0e0ce..6f48fcf 100644
--- a/Doc/lib/libcd.tex
+++ b/Doc/lib/libcd.tex
@@ -2,6 +2,7 @@
          CD-ROM access on SGI systems}
 
 \declaremodule{builtin}{cd}
+  \platform{IRIX}
 \modulesynopsis{Interface to the CD-ROM on Silicon Graphics systems.}