Fix compilation warnings
Only visible in release mode with default set of compilation warnings enabled, i.e.
CFLAGS=$XFCE_CFLAGS ./autogen.sh --disable-debug && make
with
XFCE_CFLAGS=$(echo \
-DXFCE_DISABLE_DEPRECATED \
-Wall -Wextra \
-Wno-missing-field-initializers \
-Wno-unused-parameter -Wold-style-definition \
-Wdeclaration-after-statement \
-Wmissing-declarations \
-Wmissing-noreturn -Wpointer-arith \
-Wcast-align -Wformat -Wformat-security -Wformat-y2k \
-Winit-self -Wmissing-include-dirs -Wundef \
-Wnested-externs -Wredundant-decls -Wshadow \
)
Edited by Gaël Bonithon