move docs generation

Makefile.standalone

 # The following variables will likely need to be modified, depending on where
 # and how you built LLVM & Clang. They can be overridden in a command-line
 # invocation of make, like:
 #
 #   make LLVM_SRC_PATH=<path> LIBCXX_INSTALL_PATH=<path> CLANG_PATH=<path> \
 #        PNACL_BIN_PATH=<path> ...
 #
 
 # LLVM_SRC_PATH is the path to the root of the checked out source code. This
 # directory should contain the configure script, the include/ and lib/
@@ skipping 492 matching lines @@
           PATH=$(PNACL_BIN_PATH):$(PATH) \
           $(LLVM_SRC_PATH)/../clang/tools/clang-format/clang-format-diff.py \
           -p1 -style=LLVM -i
 
 bloat: make_symlink
         nm -C -S -l pnacl-sz | \
           bloat/bloat.py --nm-output=/dev/stdin syms > build/pnacl-sz.bloat.json
         @echo See Subzero size breakdown in bloat/pnacl-sz.bloat.html
 
 docs:
-        doxygen Doxyfile
-        @echo See file://`pwd`/docs/html/index.html
+        make -C docs -f Makefile.standalone
 
 clean:
         rm -rf pnacl-sz *.o $(OBJDIR) $(SB_OBJDIR) build/pnacl-sz.bloat.json
 
 clean-all: clean
-        rm -rf build/ docs/html
+        rm -rf build/  crosstest/Output/