[llvm-shlib] Fix libLLVM-18 symlink on mingw (llvm#85554)

The TARGET_SONAME_FILE_NAME generator expression is not available on dll
target platforms.

(cherry picked from commit f849805)

Author: tstellar

llvm/tools/llvm-shlib/CMakeLists.txt

@@ -35,7 +35,7 @@ if(LLVM_BUILD_LLVM_DYLIB)
   endif()
   add_llvm_library(LLVM SHARED DISABLE_LLVM_LINK_LLVM_DYLIB OUTPUT_NAME LLVM ${INSTALL_WITH_TOOLCHAIN} ${SOURCES})
   # Add symlink for backwards compatibility with old library name
-  llvm_install_library_symlink(LLVM-${LLVM_VERSION_MAJOR}${LLVM_VERSION_SUFFIX} $<TARGET_SONAME_FILE_NAME:LLVM> SHARED FULL_DEST COMPONENT LLVM)
+  llvm_install_library_symlink(LLVM-${LLVM_VERSION_MAJOR}${LLVM_VERSION_SUFFIX} $<TARGET_FILE_NAME:LLVM> SHARED FULL_DEST COMPONENT LLVM)
 
   list(REMOVE_DUPLICATES LIB_NAMES)
   if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")