add -fvisibility=hidden flags

Author: lkeegan

build.sh

@@ -54,8 +54,10 @@ cd ..
 mkdir build
 cd build
 cmake ../qt5/qtbase -G "Ninja" \
-    -DBUILD_SHARED_LIBS=OFF \
     -DCMAKE_BUILD_TYPE=Release \
+    -DBUILD_SHARED_LIBS=OFF \
+    -DCMAKE_C_FLAGS="-fpic -fvisibility=hidden" \
+    -DCMAKE_CXX_FLAGS="-fpic -fvisibility=hidden" \
     -DCMAKE_INSTALL_PREFIX=${INSTALL_PREFIX} \
     -DCMAKE_MESSAGE_LOG_LEVEL=STATUS \
     -DCMAKE_CXX_COMPILER_LAUNCHER=ccache \