Rollup merge of rust-lang#29397 - dylanmckay:llvmdeps-deps, r=brson

Previously the file was not regenrated upon modification of `src/rustllvm` or others.

Now it will be rebuilt if `src/llvm` or `src/rustllvm` is touched.

Also added *.rs rule to 'clean' rule so that it is removed upon 'make
clean'.

Fixes rust-lang#28614.

Author: Manishearth

mk/clean.mk

@@ -65,7 +65,8 @@ clean-generic-$(2)-$(1):
          -name '*.def' -o \
          -name '*.py' -o \
          -name '*.pyc' -o \
-         -name '*.bc' \
+         -name '*.bc' -o \
+         -name '*.rs' \
          \) \
          | xargs rm -f
 	$(Q)find $(1) \