[clang] [libclang][Cygwin] Use LLVM_EXPORTED_SYMBOL_FILE (*.def file) for Cygwin (PR #147278)

[Tomohiro Kashiwada via cfe-commits]

https://github.com/kikairoya created https://github.com/llvm/llvm-project/pull/147278

This is not mandatory but recommended for completeness and consistency with MinGW.

>From 8b20535225bcbbf7153eb133217ebc87083a7a23 Mon Sep 17 00:00:00 2001
From: kikairoya <kikairoya at gmail.com>
Date: Mon, 7 Jul 2025 19:30:52 +0900
Subject: [PATCH] [libclang][Cygwin] Use LLVM_EXPORTED_SYMBOL_FILE (*.def file)
 for Cygwin

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

diff --git a/clang/tools/libclang/CMakeLists.txt b/clang/tools/libclang/CMakeLists.txt
index ac7a9a8db37c0..b6662b66206b2 100644
--- a/clang/tools/libclang/CMakeLists.txt
+++ b/clang/tools/libclang/CMakeLists.txt
@@ -92,7 +92,7 @@ if(MSVC)
   set(LLVM_EXPORTED_SYMBOL_FILE)
 endif()
 
-if (UNIX AND NOT APPLE AND NOT ${CMAKE_SYSTEM_NAME} MATCHES "AIX")
+if (UNIX AND NOT APPLE AND NOT ${CMAKE_SYSTEM_NAME} MATCHES "AIX" AND NOT CYGWIN)
   set(LLVM_EXPORTED_SYMBOL_FILE)
   set(USE_VERSION_SCRIPT ${LLVM_HAVE_LINK_VERSION_SCRIPT})
 endif()