From 7a86e4ce7368bd0a5bd390a1155db7088c1778e9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin@martin.st>
Date: Wed, 5 Dec 2018 13:47:48 +0200
Subject: [PATCH] Define _LIBCPP_ABI_UNSTABLE manually when building libcxxabi

This is set via a cmake option when building libcxx, but libcxxabi
uses the raw libcxx headers from its include directory before they
are installed.

This fixes cases of inconsistent classes seen while compiling libcxxabi
and libcxx. With potential future patches to clang to adjust how
classes are exported with dllexport, this change is needed to avoid
conflicts.
---
 build-libcxx.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/build-libcxx.sh b/build-libcxx.sh
index a6bafd6..1def9e4 100755
--- a/build-libcxx.sh
+++ b/build-libcxx.sh
@@ -167,7 +167,7 @@ build_all() {
             -DLIBCXXABI_ENABLE_NEW_DELETE_DEFINITIONS=OFF \
             -DLLVM_NO_OLD_LIBSTDCXX=TRUE \
             -DCXX_SUPPORTS_CXX11=TRUE \
-            -DCMAKE_CXX_FLAGS="$LIBCXXABI_VISIBILITY_FLAGS -D_LIBCPP_HAS_THREAD_API_WIN32 -w" \
+            -DCMAKE_CXX_FLAGS="$LIBCXXABI_VISIBILITY_FLAGS -D_LIBCPP_HAS_THREAD_API_WIN32 -D_LIBCPP_ABI_UNSTABLE -w" \
             ..
         make -j$CORES
         cd ..