applied on top of sauerbraten-2013.01.04-system-enet.patch

respect LDFLAGS, CXXFLAGS and CPPFLAGS
--- sauerbraten/src/Makefile
+++ sauerbraten/src/Makefile
@@ -1,4 +1,4 @@
-CXXFLAGS= -O3 -fomit-frame-pointer
+CXXFLAGS ?= -O3 -fomit-frame-pointer
 override CXXFLAGS+= -Wall -fsigned-char -fno-exceptions -fno-rtti
 
 PLATFORM= $(shell uname -s)
@@ -139,11 +139,11 @@
 	-$(RM) $(CLIENT_PCH) $(CLIENT_OBJS) $(SERVER_OBJS) $(MASTER_OBJS) sauer_client sauer_server sauer_master
 
 %.h.gch: %.h
-	$(CXX) $(CXXFLAGS) -o $(subst .h.gch,.tmp.h.gch,$@) $(subst .h.gch,.h,$@)
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -o $(subst .h.gch,.tmp.h.gch,$@) $(subst .h.gch,.h,$@)
 	$(MV) $(subst .h.gch,.tmp.h.gch,$@) $@
 
 %-standalone.o: %.cpp
-	$(CXX) $(CXXFLAGS) -c -o $@ $(subst -standalone.o,.cpp,$@)
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $(subst -standalone.o,.cpp,$@)
 
 $(CLIENT_OBJS): CXXFLAGS += $(CLIENT_INCLUDES)
 $(filter shared/%,$(CLIENT_OBJS)): $(filter shared/%,$(CLIENT_PCH))
@@ -168,19 +168,19 @@
 install: all
 else
 client:	$(CLIENT_OBJS)
-	$(CXX) $(CXXFLAGS) -o sauer_client $(CLIENT_OBJS) $(CLIENT_LIBS)
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) $(LDFLAGS) -o sauer_client $(CLIENT_OBJS) $(CLIENT_LIBS)
 
 server:	$(SERVER_OBJS)
-	$(CXX) $(CXXFLAGS) -o sauer_server $(SERVER_OBJS) $(SERVER_LIBS)  
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) $(LDFLAGS) -o sauer_server $(SERVER_OBJS) $(SERVER_LIBS)  
 	
 master: $(MASTER_OBJS)
-	$(CXX) $(CXXFLAGS) -o sauer_master $(MASTER_OBJS) $(MASTER_LIBS)  
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) $(LDFLAGS) -o sauer_master $(MASTER_OBJS) $(MASTER_LIBS)  
 
 shared/cube2font.o: shared/cube2font.c
-	$(CXX) $(CXXFLAGS) -c -o $@ $< `freetype-config --cflags`
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $< `freetype-config --cflags`
 
 cube2font: shared/cube2font.o
-	$(CXX) $(CXXFLAGS) -o cube2font shared/cube2font.o `freetype-config --libs` -lz
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) $(LDFLAGS) -o cube2font shared/cube2font.o `freetype-config --libs` -lz
 
 install: all
 	cp sauer_client	../bin_unix/$(PLATFORM_PREFIX)_client