libpanelapplet-2.0 not found

pilchard

I just got this error:

checking for
        libpanelapplet-2.0 >= 2.0.6
... Package libpanelapplet-2.0 was not found in the pkg-config search
path.
Perhaps you should add the directory containing `libpanelapplet-2.0.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libpanelapplet-2.0' found

configure: error: Library requirements (
        libpanelapplet-2.0 >= 2.0.6
) not met; consider adjusting the PKG_CONFIG_PATH environment variable
if your libraries are in a nonstandard prefix so pkg-config can find
them.



but there is no file named libpanelapplet-2.0.pc