Something

jjohnny@trantor:~/src/opt/gnome/lib/pkgconfig> cat libecal-1.2.pc 
prefix=/home/jjohnny/src/opt/gnome
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${prefix}/include
datarootdir=${prefix}/share
datadir=${datarootdir}

idldir=${datadir}/idl/evolution-data-server-1.2
IDL_INCLUDES=-I${idldir} -I/home/jjohnny/src/opt/gnome/share/idl/bonobo-2.0 -I/home/jjohnny/src/opt/gnome/share/idl/bonobo-activation-2.0

privincludedir=${includedir}/evolution-data-server-2.22

Name: libecal
Description: Client library for evolution calendars
Version: 2.21.1
Requires: libgnome-2.0 libbonobo-2.0 >= 2.4.2 libedataserver-1.2
Libs: -L${libdir} -lecal-1.2
Cflags: -I${privincludedir}