[llvm] [CMake] Provide `zstd::libzstd` target in `Findzstd.cmake` (PR #216968)

[via llvm-commits]

https://github.com/paperchalice updated https://github.com/llvm/llvm-project/pull/216968

>From d262a6fc115c918ae5ce890237c1abe4f0e2e5b4 Mon Sep 17 00:00:00 2001
From: paperchalice <liujunchang97 at outlook.com>
Date: Tue, 18 Aug 2026 17:16:30 +0800
Subject: [PATCH] [CMake] Provide `zstd::libzstd` target in `Findzstd.cmake`

If enable both zstd and cpp-httplib, cmake will throw an error because not all zstd targets are defined.
---
 llvm/cmake/modules/Findzstd.cmake | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/llvm/cmake/modules/Findzstd.cmake b/llvm/cmake/modules/Findzstd.cmake
index dbfaadb5de2b8..d166115d5da9b 100644
--- a/llvm/cmake/modules/Findzstd.cmake
+++ b/llvm/cmake/modules/Findzstd.cmake
@@ -61,6 +61,13 @@ if(zstd_FOUND)
         INTERFACE_INCLUDE_DIRECTORIES "${zstd_INCLUDE_DIR}"
         IMPORTED_LOCATION "${zstd_STATIC_LIBRARY}")
   endif()
+  if(TARGET zstd::libzstd_shared)
+    add_library(zstd::libzstd INTERFACE IMPORTED)
+    target_link_libraries(zstd::libzstd INTERFACE zstd::libzstd_shared)
+  else()
+    add_library(zstd::libzstd INTERFACE IMPORTED)
+    target_link_libraries(zstd::libzstd INTERFACE zstd::libzstd_static)
+  endif()
 endif()
 
 unset(zstd_STATIC_LIBRARY_SUFFIX)