Fix for correctly including climits on certain platforms {DragonFlyBSD}.

src/Makefile.am

@@ -14,7 +14,7 @@ $(LIBLEVELDB): $(LIBMEMENV)
 $(LIBLEVELDB) $(LIBMEMENV):
 	@echo "Building LevelDB ..." && $(MAKE) -C $(@D) $(@F) CXX="$(CXX)" \
 	  CC="$(CC)" PLATFORM=$(TARGET_OS) AR="$(AR)" $(LEVELDB_TARGET_FLAGS) \
-          OPT="$(CXXFLAGS) $(CPPFLAGS)"
+          OPT="$(CXXFLAGS) $(CPPFLAGS) -D__STDC_LIMIT_MACROS"
 endif
 
 BITCOIN_CONFIG_INCLUDES=-I$(builddir)/config