Remove building llvm2ice.build_atts from Subzero build.

Makefile.standalone

Index: Makefile.standalone
diff --git a/Makefile.standalone b/Makefile.standalone
index feae52cd913dac7faf576f71353714c66e9410e7..aa584de8cfacaaa5e090edd1b3f29c17e1950675 100644
--- a/Makefile.standalone
+++ b/Makefile.standalone
@@ -116,10 +116,11 @@ OBJS=$(patsubst %.cpp, $(OBJDIR)/%.o, $(SRCS))
 # Keep all the first target so it's the default.
 all: $(OBJDIR)/llvm2ice make_symlink
 
-make_symlink: $(OBJDIR)/llvm2ice $(OBJDIR)/llvm2ice.build_atts
-	rm -rf llvm2ice llvm2ice.build_atts
+make_symlink: $(OBJDIR)/llvm2ice
+	rm -rf llvm2ice
 	ln -s $(OBJDIR)/llvm2ice
-	ln -s $(OBJDIR)/llvm2ice.build_atts
+	# Build Attributes:
+	@$(OBJDIR)/llvm2ice --build-atts
 
 .PHONY: all make_symlink
 
@@ -128,7 +129,6 @@ make_symlink: $(OBJDIR)/llvm2ice $(OBJDIR)/llvm2ice.build_atts
 $(OBJDIR)/llvm2ice: $(OBJS)
 	$(CXX) $(LDFLAGS) -o $@ $^ $(LLVM_LDFLAGS) -ldl \
                -Wl,-rpath=$(abspath $(LIBCXX_INSTALL_PATH)/lib)
-	$@ --build-atts > $@.build_atts
 
 # TODO: Be more precise than "*.h" here and elsewhere.
 $(OBJS): $(OBJDIR)/%.o: src/%.cpp src/*.h src/*.def
@@ -166,7 +166,7 @@ format-diff:
 	$(CLANG_FORMAT_DIFF) -p1 -style=LLVM -i
 
 clean:
-	rm -rf llvm2ice llvm2ice.build_atts *.o $(OBJDIR)
+	rm -rf llvm2ice *.o $(OBJDIR)
 
 clean-all: clean
 	rm -rf build/