Fails to build with up to date XFCE. Requires `libxfce4panel-1.0`, but `libxfce4panel-2.0` is present.

[dreirund]

Configuration fails for me -- seems to be not compatible with up to date xfce:

[...]
checking for LIBGTOP... yes
checking for XFCE4... no
configure: error: in `/tmp/makepkg/build/xfce4-multiload-nandhp-plugin-git/src/multiload-nandhp':
configure: error: --with-xfce4 was given, but test failed
See `config.log' for more details

config.log shows:

[...]
configure:16214: $PKG_CONFIG --exists --print-errors "$pkg_modules"
Package libxfce4panel-1.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `libxfce4panel-1.0.pc'
to the PKG_CONFIG_PATH environment variable
Package 'libxfce4panel-1.0', required by 'virtual:world', not found
configure:16217: $? = 1
configure:16231: $PKG_CONFIG --exists --print-errors "$pkg_modules"
Package libxfce4panel-1.0 was not found in the pkg-config search path.
Perhaps you should add the directory containing `libxfce4panel-1.0.pc'
to the PKG_CONFIG_PATH environment variable
Package 'libxfce4panel-1.0', required by 'virtual:world', not found
configure:16234: $? = 1
configure:16248: result: no
Package 'libxfce4panel-1.0', required by 'virtual:world', not found
configure:16266: error: in `/tmp/makepkg/build/xfce4-multiload-nandhp-plugin-git/src/multiload-nandhp':
configure:16268: error: --with-xfce4 was given, but test failed
[...]

I have the files /usr/lib/libxfce4panel-2.0.so and /usr/lib/pkgconfig/libxfce4panel-2.0.pc

Regards!