tinyxml2: build with -fPIC

packages/textproc/tinyxml2/package.mk

@@ -32,6 +32,10 @@ PKG_LONGDESC="TinyXML2 is a simple, small, C++ XML parser that can be easily int
 PKG_IS_ADDON="no"
 PKG_AUTORECONF="no"
 
+pre_configure_target() {
+  export CFLAGS="$CFLAGS -fPIC"
+}
+
 configure_target() {
   cmake -DCMAKE_TOOLCHAIN_FILE=$CMAKE_CONF \
         -DCMAKE_INSTALL_PREFIX=/usr \