diff --git a/build/pkg-config.sh b/build/pkg-config.sh
index 7c021dbce..18ec25be6 100755
--- a/build/pkg-config.sh
+++ b/build/pkg-config.sh
@@ -1,5 +1,9 @@
 #!/bin/sh -e
 
+# This is a wrapper for pkg-config which helps with cross-compiling;
+# it sets up environment variables to pkg-config searches for
+# libraries in the sysroot where a copy of this script is located.
+
 BIN=`dirname $0`
 ROOT=`dirname "$BIN"`