diff --git a/SysBuild/guibased/qt-all-opensource b/SysBuild/guibased/qt-all-opensource
index d1deeb2..98e545a 100644
--- a/SysBuild/guibased/qt-all-opensource
+++ b/SysBuild/guibased/qt-all-opensource
@@ -87,8 +87,8 @@ premk() {
 
 mk32() {
 	yes "o"| \
-	CC="gcc $BUILDOPTIONS32" \
-	CXX="g++ $BUILDOPTIONS32" \
+	CC="gcc $BUILDOPTIONS32 -fvisibility=hidden" \
+	CXX="g++ $BUILDOPTIONS32 -fvisibility=hidden" \
 	USE_ARCH=$UARCH \
 	../qt-*/configure -prefix /opt/qt-4 \
 		    -docdir /usr/share/doc/qt-4 \
@@ -110,8 +110,8 @@ mk() {
 		ADDOPTIONS="-libdir /opt/qt-4/lib64"
 	fi
 	yes "o"| \
-	CC="gcc $BUILDOPTIONS" \
-	CXX="g++ $BUILDOPTIONS" \
+	CC="gcc $BUILDOPTIONS -fvisibility=hidden" \
+	CXX="g++ $BUILDOPTIONS -fvisibility=hidden" \
 	USE_ARCH=$UARCH \
 	../qt-*/configure -prefix /opt/qt-4 \
 	                  -docdir /usr/share/doc/qt-4 \