+# Build clang if present.
+OPTIONAL_PARALLEL_DIRS := clang
+
+# NOTE: The tools are organized into five groups of four consisting of one
+# large and three small executables. This is done to minimize memory load
+# in parallel builds. Please retain this ordering.
+DIRS := llvm-config
+PARALLEL_DIRS := opt llvm-as llvm-dis \
+ llc llvm-ranlib llvm-ar llvm-nm \
+ llvm-ld llvm-prof llvm-link \
+ lli gccas gccld llvm-extract llvm-db \
+ bugpoint llvm-bcanalyzer llvm-stub \
+ llvm-mc llvmc
+
+# Let users override the set of tools to build from the command line.
+ifdef ONLY_TOOLS
+ OPTIONAL_PARALLEL_DIRS :=
+ PARALLEL_DIRS := $(ONLY_TOOLS)
+endif