Add doxygen build target

Makefile.standalone

Index: Makefile.standalone
diff --git a/Makefile.standalone b/Makefile.standalone
index 5f2686ba8f7788db34b49715bed3689905a65640..8dafc83a0a09a3450bc82f5c521846dd56901177 100644
--- a/Makefile.standalone
+++ b/Makefile.standalone
@@ -234,7 +234,7 @@ make_symlink: $(OBJDIR)/pnacl-sz
 	@echo "Build Attributes:"
 	@$(OBJDIR)/pnacl-sz --build-atts
 
-.PHONY: all make_symlink runtime bloat sb
+.PHONY: all make_symlink runtime bloat sb docs
 
 $(OBJDIR)/pnacl-sz: $(OBJS)
 	$(CXX) $(LDFLAGS) -o $@ $^ $(LLVM_LDFLAGS) \
@@ -338,8 +338,12 @@ bloat: make_symlink
 	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:

[Jim Stichnoth, 2015/06/26 00:56:18]

Seems like this should still depend on the Doxyfile?  (not a big deal either
way)

[ascull, 2015/06/29 17:05:11]

As it is a PHONY target it is always out of date so dependencies don't make a
difference. It would be better to have proper dependencies but I couldn't get
that to work properly for doxygen.

+	doxygen Doxyfile
+	@echo See file://`pwd`/docs/html/index.html
+
 clean:
 	rm -rf pnacl-sz *.o $(OBJDIR) $(SB_OBJDIR) build/pnacl-sz.bloat.json
 
 clean-all: clean
-	rm -rf build/
+	rm -rf build/ docs/