fix on os x

Makefile

@@ -42,7 +42,7 @@ ifneq ($(GIT_VERSION),"")
 endif
 
 REQUIRED_CFLAGS = $(LIBUV_FLAGS) $(SODIUM_FLAGS) -I$(REPO)/include -std=c99 $(CFLAGS) $(DEBUG_FLAGS) $(VER_FLAGS) -Wall -fPIC
-REQUIRED_CXXFLAGS = $(LIBUV_FLAGS) $(SODIUM_FLAGS) -I$(REPO)/include -std=c++17 $(CXXFLAGS) $(DEBUG_FLAGS) $(VER_FLAGS) -Wall -fPIC
+REQUIRED_CXXFLAGS = $(LIBUV_FLAGS) $(SODIUM_FLAGS) -I$(REPO)/include -std=c++14 $(CXXFLAGS) $(DEBUG_FLAGS) $(VER_FLAGS) -Wall -fPIC
 LIB_LDFLAGS = -ljemalloc $(SODIUM_LIBS) $(LIBUV_LIBS) -lm -lstdc++
 REQUIRED_LDFLAGS = -L$(REPO) -lllarp 
 TEST_LDFLAGS = $(STATIC_LIB) $(LIB_LDFLAGS)

llarp/buffer.cpp

@@ -4,7 +4,7 @@
 extern "C" {
 
 size_t llarp_buffer_size_left(llarp_buffer_t *buff) {
-  std::ptrdiff_t diff = buff->cur - buff->base;
+  auto diff = buff->cur - buff->base;
   if (diff < 0) {
     return 0;
   } else if (diff > buff->sz)