c2rust tests adapted for use with Vellvm

Each c2rust test directory has:

• a linked.ll file that contains the combined LLVM IR code
• a vellvm_tests.ll file that contains some Vellvm-style assertions for use with its testing framework

To run a test, execute the following command, where $(PATH_TO_VELLVM_SRC) is the directory where the vellvm executable and libll files live and $(TESTDIR) is one of the c2rust test directories.

$(PATH_TO_VELLVM_SRC)/vellvm -v -l $(PATH_TO_VELLVM_SRC)/libll/rust-intrinsics.ll -l $(TESTDIR)/linked.ll -test-file $(TESTDIR)/vellvm_tests.ll

For example, to run it on the c2rust tests in the example directory, do:

~/vellvm/src/vellvm -v -l ~/vellvm/src/vellvm/libll/rust-intrinsics.ll -l example/linked.ll -test-file example/vellvm_tests.ll