Add llvm and build files to gitignore

.gitignore

@@ -27,10 +27,7 @@ cfg.foo.dot
 lit.site.cfg
 *.dot
 JITTests.exports
-llvm/include/llvm/Config/config.h
-llvm/include/llvm/Config/llvm-config.h
-llvm/include/llvm/Support/DataTypes.h
-llvm/test/VISC/parboil/benchmarks/*/run
-llvm/test/VISC/parboil/benchmarks/*/build
-llvm/build
-llvm/install
+build/
+hpvm/install
+hpvm/llvm
+hpvm/llvm-9.0.0.src.tar.xz