message: Rename `CFLAGS` (C) to `CXXFLAGS` (C++)
diff: @@ -9,14 +9,14 @@ NAS2DINCLUDEDIR := $(NAS2DDIR)include/
  NAS2DLIBDIR := $(NAS2DDIR)lib/
  NAS2DLIB := $(NAS2DLIBDIR)libnas2d.a
  -CFLAGS := -std=c++17 -g -Wall -Wno-unknown-pragmas -I$(NAS2DINCLUDEDIR) $(shell sdl2-config --cflags)
  +CXXFLAGS := -std=c++17 -g -Wall -Wno-unknown-pragmas -I$(NAS2DINCLUDEDIR) $(shell sdl2-config --cflags)
  LDFLAGS := -lstdc++ -lm -L$(NAS2DLIBDIR) -lnas2d \
  $(shell sdl2-config --libs) -lSDL2 -lSDL2_image -lSDL2_mixer -lSDL2_ttf \
  -lphysfs -lGL -lGLEW
  DEPFLAGS = -MT $@ -MMD -MP -MF $(OBJDIR)$*.Td
  -COMPILE.cpp = $(CXX) $(DEPFLAGS) $(CFLAGS) $(TARGET_ARCH) -c
  +COMPILE.cpp = $(CXX) $(DEPFLAGS) $(CXXFLAGS) $(TARGET_ARCH) -c
  POSTCOMPILE = @mv -f $(OBJDIR)$*.Td $(OBJDIR)$*.d && touch $@
  SRCS := $(shell find $(SRCDIR) -name '*.cpp')
  