From 7a576ff05698cb1be121f6da0cd22f8e9aaa86b9 Mon Sep 17 00:00:00 2001
From: YAMAMOTO Takashi <yamamoto@midokura.com>
Date: Wed, 19 Jan 2022 11:16:56 +0900
Subject: [PATCH] boards/sim/sim/sim/scripts/Make.defs: Disable libcxx
 availability macros

---
 boards/sim/sim/sim/scripts/Make.defs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/boards/sim/sim/sim/scripts/Make.defs b/boards/sim/sim/sim/scripts/Make.defs
index be3fc1f763..c8897d9fb9 100644
--- a/boards/sim/sim/sim/scripts/Make.defs
+++ b/boards/sim/sim/sim/scripts/Make.defs
@@ -122,6 +122,14 @@ ifeq ($(CONFIG_LIBCXX),y)
     # XXX what to do for windows?
     CXXFLAGS += -D__GLIBCXX__
   endif
+
+  # Disable availability macros.
+  # The availability on Host OS is not likely appropriate for NuttX.
+  #
+  # Note: When compiling NuttX apps, we undefine __APPLE__.
+  # It makes libcxx __availability header unhappy.
+  # https://github.com/llvm/llvm-project/blob/2e2999cd44f6ec9a5e396fa0113497ea82582f69/libcxx/include/__availability#L258
+  CXXFLAGS += -D_LIBCPP_DISABLE_AVAILABILITY
 endif
 
 ifeq ($(CONFIG_SIM_ASAN),y)