Patch #500136: Update Update ext build documentation. 2.2.1 candidate.
diff --git a/Doc/ext/ext.tex b/Doc/ext/ext.tex
index 9ad6523..b4130d1 100644
--- a/Doc/ext/ext.tex
+++ b/Doc/ext/ext.tex
@@ -52,7 +52,7 @@
 
 \input{extending}
 \input{newtypes}
-\input{unix}
+\input{building}
 \input{windows}
 \input{embedding}