Bug #1450: Illumos should be buildable with GCC4
newer gcc, and sanity, would benefit from a newer libdwarf
Newer GCC requires a newer libdwarf with more robust relocation support, something which we would benefit from in general (our current relocation support is x86-specific, and home grown).
Unfortunately, very new libdwarf would expose #1879, so I propose to take the libdwarf I initially used in the gcc branch, and thus have tested heavily, from early 2011.
This is, at present, used only while ctfconverting DWARF objects (and thus, by the GCC-build, either 3 or 4).