Move to Weld as the build system.

Change-Id: I7c9704f3f310cf7e5410db148a9c4c589914b0f2
diff --git a/makefile b/makefile
index 269e14e..50cb63a 100644
--- a/makefile
+++ b/makefile
@@ -1,44 +1,3 @@
-.PHONY: all clean
+config_file := ./config.mk
 
-CXX = c++
-LDFLAGS =
-CXXFLAGS = -I. -std=c++17
-MKDIR_P = mkdir -p
-
-EXE = exe/hello-world-ng
-TEST = t/greeting-test
-
-mod_OBJ = mod/greeting.o
-hello_world_ng_OBJ = exe/hello-world-ng.o
-greeting_test_OBJ = t/greeting-test.o
-
-OBJ = $(hello_world_ng_OBJ) $(mod_OBJ)
-
-all: $(EXE)
-
-test: $(TEST)
-	@for x in $^; do \
-		echo $$x; \
-		$$x; \
-	done
-
-test-junit: $(TEST)
-	$(MKDIR_P) test-results/t
-	@for x in $^; do \
-		echo $$x -r junit -o test-results/$$x.xml --success; \
-		$$x -r junit -o test-results/$$x.xml --success || :; \
-	done
-
-clean:
-	$(RM) $(OBJ)
-	$(RM) $(EXE)
-	$(RM) -r test-results
-
-exe/hello-world-ng: $(hello_world_ng_OBJ) $(mod_OBJ)
-	$(CXX) $(CXXFLAGS) $(LDFLAGS) -o $@ $^
-
-t/greeting-test: $(greeting_test_OBJ) $(mod_OBJ)
-	$(CXX) $(CXXFLAGS) $(LDFLAGS) -o $@ $^
-
-%.o: %.cpp
-	$(CXX) $(CXXFLAGS) -o $@ -c $<
+include weld/weld.mk