File obey-cflags.patch of Package bermuda

diff --git a/Makefile b/Makefile
index d843de0..34a0733 100644
--- a/Makefile
+++ b/Makefile
@@ -11,7 +11,7 @@ VORBIS_LIBS = -lvorbisfile -lvorbis -logg
 SDL_CFLAGS = `sdl2-config --cflags`
 SDL_LIBS = `sdl2-config --libs` -lSDL2_mixer
 
-CXXFLAGS = -g -O -Wall $(SDL_CFLAGS) $(DEFINES)
+CXXFLAGS += -g -O -Wall $(SDL_CFLAGS) $(DEFINES)
 
 OBJDIR = obj