diff --git a/development/LyX-Mac-binary-release.sh b/development/LyX-Mac-binary-release.sh
index 63bd3ab08c..c3e756f636 100644
--- a/development/LyX-Mac-binary-release.sh
+++ b/development/LyX-Mac-binary-release.sh
@@ -9,7 +9,7 @@
 
 QtAPI=${QtAPI:-"-cocoa"}
 QtVersion=${QtVersion:-"4.6.3"}
-QtSourceVersion="qt-everywhere-opensource-src-${QtVersion}"
+QtSourceVersion=${QtSourceVersion:-"qt-everywhere-opensource-src-${QtVersion}"}
 QtBuildSubDir="qt-${QtVersion}-build${QtAPI}"
 QtConfigureOptions=${QtConfigureOptions:-"-release"}