[libcxx-commits] [libcxxabi] fix cmake config error in llvm-libgcc (PR #187280)

[Andrew Marshall via libcxx-commits]

https://github.com/planetmarshall created https://github.com/llvm/llvm-project/pull/187280

Allow libcxxabi to build if libunwind is not present in `LLVM_ENABLE_RUNTIMES`, provided `llvm-libgcc` is enabled.

Closes #100888 

>From e8fb3a1cc92bdb1a0e01b8c0b7e8e979fa039e8a Mon Sep 17 00:00:00 2001
From: Andrew Marshall <planetmarshalluk at gmail.com>
Date: Wed, 18 Mar 2026 14:08:11 +0000
Subject: [PATCH] fix cmake config error in llvm-libgcc

---
 libcxxabi/CMakeLists.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libcxxabi/CMakeLists.txt b/libcxxabi/CMakeLists.txt
index 2b67c5972339e..1a76e19f7d7b3 100644
--- a/libcxxabi/CMakeLists.txt
+++ b/libcxxabi/CMakeLists.txt
@@ -53,7 +53,7 @@ option(LIBCXXABI_ENABLE_ASSERTIONS "Enable assertions independent of build mode.
 option(LIBCXXABI_ENABLE_PEDANTIC "Compile with pedantic enabled." OFF)
 option(LIBCXXABI_ENABLE_WERROR "Fail and stop if a warning is triggered." OFF)
 option(LIBCXXABI_USE_LLVM_UNWINDER "Build and use the LLVM unwinder." ON)
-if (LIBCXXABI_USE_LLVM_UNWINDER AND NOT "libunwind" IN_LIST LLVM_ENABLE_RUNTIMES)
+if (LIBCXXABI_USE_LLVM_UNWINDER AND (NOT "libunwind" IN_LIST LLVM_ENABLE_RUNTIMES AND NOT LLVM_LIBGCC_EXPLICIT_OPT_IN))
   message(FATAL_ERROR "LIBCXXABI_USE_LLVM_UNWINDER is set to ON, but libunwind is not specified in LLVM_ENABLE_RUNTIMES.")
 endif()
 option(LIBCXXABI_ENABLE_STATIC_UNWINDER "Statically link the LLVM unwinder." OFF)