I just installed a GNU/Linux Ubuntu 12.04.4 LTS server (Amazon EC2 image in case it's relevant) with "sudo apt-get install xorg-dev", but tbb42_20140122oss/examples/common/gui/Makefile.gmake would not recognise the installed libraries (see http://packages.ubuntu.com/precise/libx11-dev, [list of files], to see what paths were used instead). I don't remember this being an issue with the Ubuntu desktop installation on my previous laptop computer, which is a bit strange.
The workaround was easy enough at lines 50 and 58 assuming a 64-bit build, and even blending in with the general 32/64 support would be doable, but who knows what other paths are out there in the wild?
Also, this worked without changing UI_CXXFLAGS or LIBS (/usr/X11R6/...), which also seemed a bit odd.
Does anybody have any suggestions about possible other locations, or a comment on this particular situation, that might be relevant to a patch?