cmake finds wrong PROTOBUFC_INCLUDE_DIR?

[z0rti]

I'm trying to compile it to be installed to /opt/umurmur
(i compiled and installed libprotobuf + libprotobuf-c there too)

$ pkg-config --cflags libprotobuf-c
-I/opt/umurmur/include

$ cmake .. -DCMAKE_INSTALL_PREFIX=/opt/umurmur
[...]
-- Found ProtobufC: /opt/umurmur/include/google/protobuf-c
[...]

so in CMakeCache.txt it sets PROTOBUFC_INCLUDE_DIR:PATH=/opt/umurmur/include/google/protobuf-c
where protobuf-c.h is, so
Mumble.pb-c.h:#include <protobuf-c/protobuf-c.h>
would not find it

Quickfix: add -DPROTOBUFC_INCLUDE_DIR="/opt/umurmur/include/google" to cmake