add config support

includes/tomlc17-R260618/test/cpp/Makefile

@@ -0,0 +1,49 @@
+CFLAGS = -std=c17 -fsanitize=address,undefined -Wmissing-declarations -Wall -Wextra -MMD
+EXEC = test1
+
+ifdef DEBUG
+    CFLAGS += -O0 -g
+else
+    CFLAGS += -O3 -DNDEBUG
+endif
+
+CXXFLAGS = $(subst -std=c17,-std=c++20,$(CFLAGS))
+
+# Test for C++20 support
+CXX20_SUPPORT := $(shell echo "int main(){}" | $(CXX) -std=c++20 -x c++ -c - -o /dev/null 2>/dev/null && echo yes || echo no)
+
+ifeq ($(CXX20_SUPPORT),yes)
+
+all: $(EXEC)
+
+test1: test1.cpp
+	$(CXX) $(CXXFLAGS) -o $@ $@.cpp -L../../src -ltomlc17
+
+test: all
+	@echo
+	@echo =========================
+	@echo == cpp test
+	@echo =========================
+	./test1
+
+else
+
+all:
+	@echo "Skipped because C++20 not available"
+
+test: 
+	@echo "Skipped because C++20 not available"
+
+endif
+
+-include test1.d
+
+clean:
+	rm -f *.o *.d $(EXEC)
+
+distclean: clean
+
+format:
+	clang-format -i *.cpp
+
+.PHONY: all clean distclean format test