For some dumb reason, llvm-config doesn't provide the flags to link
against the dynamic library copy of LLVM (as opposed to static), so the
script has to guess the library name. However, in some installations
(such as mine), there is no dynamic copy, which caused Dolphin to fail
to link. Change the script to do a link test. If it fails, one option
would be to fall back on static linking, but I just have it fail to
detect LLVM, because statically linking Dolphin against LLVM is really
not a great idea - huge binary, long link time.