[libcxx] fix CMake install target for libc++experimental

[Fabio]

Summary

The install command for lib cxx was not getting the right target since it used two unused variables as input instead of the correct target.
This fixes installation for libc++experimental

[smeenai]

This was fixed by rGce36c5ab643a5ced7da2034288bbfbdd7193058b

[Fabio]

Thanks problem fixed, that makes this one obsolete.

[ldionne]

In D76183#1941028, @Fabio wrote:

Thanks problem fixed, that makes this one obsolete.

Sorry, this review never came up in my queue. I think this would be solved by the new automatic review groups.

libcxx/src/CMakeLists.txt

if (LIBCXX_INSTALL_LIBRARY)
   if (LIBCXX_INSTALL_STATIC_LIBRARY)
     install(TARGETS cxx_static
       ARCHIVE DESTINATION ${LIBCXX_INSTALL_PREFIX}${LIBCXX_INSTALL_LIBRARY_DIR} COMPONENT cxx
       LIBRARY DESTINATION ${LIBCXX_INSTALL_PREFIX}${LIBCXX_INSTALL_LIBRARY_DIR} COMPONENT cxx
       RUNTIME DESTINATION ${LIBCXX_INSTALL_PREFIX}bin COMPONENT cxx)
   endif()
 
   if(LIBCXX_INSTALL_EXPERIMENTAL_LIBRARY)
-    install(TARGETS ${LIBCXX_INSTALL_TARGETS} ${experimental_lib}
+    install(TARGETS cxx_experimental
       LIBRARY DESTINATION ${LIBCXX_INSTALL_PREFIX}${LIBCXX_INSTALL_LIBRARY_DIR} COMPONENT cxx
       ARCHIVE DESTINATION ${LIBCXX_INSTALL_PREFIX}${LIBCXX_INSTALL_LIBRARY_DIR} COMPONENT cxx
       RUNTIME DESTINATION ${LIBCXX_INSTALL_PREFIX}bin COMPONENT cxx)
   endif()
 
   # NOTE: This install command must go after the cxx install command otherwise
   # it will not be executed after the library symlinks are installed.
   if (LIBCXX_ENABLE_SHARED AND LIBCXX_ENABLE_ABI_LINKER_SCRIPT)