Just figured out how to build telepathy-qt4 in an alternate prefix and also look for dependencies in that prefix as well. Since I don’t use cmake much these days, figured I’d post this so I could go and look back at it later. Depends on this fix.
PKG_CONFIG_PATH=~/the/prefix cmake -DCMAKE_INSTALL_PREFIX=~/the/prefix .make install
Or if on a 64-bit system:
PKG_CONFIG_PATH=~/the/prefix cmake -DCMAKE_INSTALL_PREFIX=/data/build/telepathy -DLIB_SUFFIX=64 .make install