Pass compiler flags down into leveldb make

Fixes issue#2288. Includes cleanups from Luke's pull 2243.

src/makefile.osx

@@ -62,7 +62,7 @@ ifdef RELEASE
 # the same way.
 CFLAGS = -mmacosx-version-min=10.5 -arch i386 -O3
 else
-CFLAGS = -g
+DEBUGFLAGS = -g
 endif
 
 # ppc doesn't work because we don't support big-endian
@@ -70,6 +70,7 @@ CFLAGS += -Wall -Wextra -Wformat -Wformat-security -Wno-unused-parameter \
     $(DEBUGFLAGS) $(DEFS) $(INCLUDEPATHS)
 
 OBJS= \
+    leveldb/libleveldb.a \
     obj/alert.o \
     obj/version.o \
     obj/checkpoints.o \
@@ -130,8 +131,7 @@ LIBS += $(CURDIR)/leveldb/libleveldb.a $(CURDIR)/leveldb/libmemenv.a
 DEFS += $(addprefix -I,$(CURDIR)/leveldb/include)
 DEFS += $(addprefix -I,$(CURDIR)/leveldb/helpers)
 leveldb/libleveldb.a:
-	@echo "Building LevelDB ..." && cd leveldb && $(MAKE) libleveldb.a libmemenv.a && cd ..
-obj/leveldb.o: leveldb/libleveldb.a
+	@echo "Building LevelDB ..." && cd leveldb && $(MAKE) CC=$(CC) CXX=$(CXX) OPT="$(CFLAGS)" libleveldb.a libmemenv.a && cd ..
 
 # auto-generated dependencies:
 -include obj/*.P
@@ -171,5 +171,6 @@ clean:
 	-rm -f obj/*.P
 	-rm -f obj-test/*.P
 	-rm -f obj/build.h
+	-cd leveldb && $(MAKE) clean || true
 
 FORCE: