[llvm] [llvm-config] Make llvm-config --system-libs obey LLVM_USE_STATIC_ZSTD. (PR #93754)

[Kyle Huey via llvm-commits]

https://github.com/khuey created https://github.com/llvm/llvm-project/pull/93754

LLVM's build system does the right thing but LLVM_SYSTEM_LIBS ends up containing the shared library. Emit the static library instead when appropriate.

CC @MaskRay since zstd compression is relevant to his interests.

>From ecb1ff20c69d0a15b619a13a3a43b9f2c6ec9e23 Mon Sep 17 00:00:00 2001
From: Kyle Huey <khuey at kylehuey.com>
Date: Wed, 29 May 2024 16:33:55 -0700
Subject: [PATCH] [llvm-config] Make llvm-config --system-libs obey
 LLVM_USE_STATIC_ZSTD.

LLVM's build system does the right thing but LLVM_SYSTEM_LIBS ends up
containing the shared library. Emit the static library instead when
appropriate.
---
 llvm/lib/Support/CMakeLists.txt | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Support/CMakeLists.txt b/llvm/lib/Support/CMakeLists.txt
index 03e888958a071..1ab5bd370c480 100644
--- a/llvm/lib/Support/CMakeLists.txt
+++ b/llvm/lib/Support/CMakeLists.txt
@@ -321,8 +321,12 @@ if(LLVM_ENABLE_ZSTD)
   if(NOT zstd_library)
     get_property(zstd_library TARGET ${zstd_target} PROPERTY LOCATION)
   endif()
-  get_library_name(${zstd_library} zstd_library)
-  set(llvm_system_libs ${llvm_system_libs} "${zstd_library}")
+  if (zstd_target STREQUAL zstd::libzstd_shared)
+    get_library_name(${zstd_library} zstd_library)
+    set(llvm_system_libs ${llvm_system_libs} "${zstd_library}")
+  else()
+    set(llvm_system_libs ${llvm_system_libs} "${zstd_STATIC_LIBRARY}")
+  endif()
 endif()
 
 if(LLVM_ENABLE_TERMINFO)