[libc++] Fix how we pass /MANIFEST flag on Windows without clang-cl (#96967)

If we're compiling with Clang (not clang-cl) on Windows, we need to use
-Xlinker to pass the /MANIFEST option.

Fixes #96430

Author: ldionne

libcxx/src/CMakeLists.txt

@@ -275,8 +275,13 @@ if (LIBCXX_ENABLE_SHARED)
     # Since we most likely do not have a mt.exe replacement, disable the
     # manifest bundling.  This allows a normal cmake invocation to pass which
     # will attempt to use the manifest tool to generate the bundled manifest
-    set_target_properties(cxx_shared PROPERTIES
-                          APPEND_STRING PROPERTY LINK_FLAGS " /MANIFEST:NO")
+    if (${CMAKE_CXX_COMPILER_FRONTEND_VARIANT} STREQUAL "MSVC")
+      set_target_properties(cxx_shared PROPERTIES
+                            APPEND_STRING PROPERTY LINK_FLAGS " /MANIFEST:NO")
+    else()
+      set_target_properties(cxx_shared PROPERTIES
+                            APPEND_STRING PROPERTY LINK_FLAGS " -Xlinker /MANIFEST:NO")
+    endif()
   endif()
 endif()