diff --git a/libraries/osx/build-osx-libs.sh b/libraries/osx/build-osx-libs.sh
index 475d782387..8efcc9daee 100755
--- a/libraries/osx/build-osx-libs.sh
+++ b/libraries/osx/build-osx-libs.sh
@@ -346,7 +346,7 @@ then
   pushd build-release
 
   # disable XML and richtext support, to avoid dependency on expat
-  CONF_OPTS="--prefix=$INSTALL_DIR --disable-shared --enable-unicode --with-cocoa --with-opengl --with-libiconv-prefix=ICONV_DIR --disable-richtext --without-expat --without-sdl"
+  CONF_OPTS="--prefix=$INSTALL_DIR --disable-shared --enable-unicode --with-cocoa --with-opengl --with-libiconv-prefix=${ICONV_DIR} --disable-richtext --without-expat --without-sdl"
   # wxWidgets configure now defaults to targeting 10.5, if not specified,
   # but that conflicts with our flags
   if [[ $MIN_OSX_VERSION && ${MIN_OSX_VERSION-_} ]]; then