I am using the current HEAD branch in git. When calling autogen, I get the error checking for libxfce4panel-2.0 >= 4.10.0git... not found *** The required package libxfce4panel-2.0 was not found on your system. but I am wondering where this lib should come from. The $PREFIX is set to a local directory, and so is the PKG_CONFIG_PATH.
LD_LIBRARY_PATH has to be set to $PREFIX/lib
But the current version of xfce4-panel only generates a libxfce4panel-1, so the dependency is still unresolved.