[RFC v2 2/9] move some rsp bits into rsp-low.h

[Tom Tromey]

Yao> We also need to compile rsp-low.c for IPA, and link rsp-low-ipa.o
Yao> in IPA.  I get the ipa build error below,

Sorry Yao.
Could you mention again what version of UST is supported?
I tried just now with:

    barimba. rpm -q lttng-ust-devel
    lttng-ust-devel-2.0.8-1.fc18.x86_64

but it doesn't work:

    checking for ust... no

Tom