Being a linux nub, I hesitate to try to modify the readme myself.
I tried libdb++dev which pulled in 5.1, which allowed me to start compilng. I then ran into:
src/net.cpp:18:32: fatal error: miniupnpd/miniwget.h: no such file or directory
I then found:
qmake "USE_UPNP=-"
instead of
qmake "USE_UPNP="
that allowed me to fully compile the latest git.
M