diff --git a/doc/src/sgml/installation.sgml b/doc/src/sgml/installation.sgml
index 5da97c5..cd3755b 100644
--- a/doc/src/sgml/installation.sgml
+++ b/doc/src/sgml/installation.sgml
@@ -542,9 +542,18 @@ su - postgres
This script will run a number of tests to determine values for various
system dependent variables and detect any quirks of your
operating system, and finally will create several files in the
- build tree to record what it found. (You can also run
+ build tree to record what it found. You can also run
configure in a directory outside the source
- tree if you want to keep the build directory separate.)
+ tree, if you want to keep the build directory separate. This
+ procedure is also called a
+ VPATHVPATH
+ build. Here's how:
+
+mkdir build_dir
+cd build_dir
+/path/to/source/tree/configure [options go here]
+gmake
+