Re-enable linker scripts after fixing bad CMake

llvm-svn: 250472
diff --git a/libcxx/lib/CMakeLists.txt b/libcxx/lib/CMakeLists.txt
index d02b8c5..ec3085b 100644
--- a/libcxx/lib/CMakeLists.txt
+++ b/libcxx/lib/CMakeLists.txt
@@ -140,7 +140,7 @@
   # is a target name and not a library. Ex cxxabi_shared.
   set(SCRIPT_ABI_LIBNAME "${LIBCXX_CXX_ABI_LIBRARY}")
   if (SCRIPT_ABI_LIBNAME STREQUAL "cxxabi_shared")
-    set("${SCRIPT_ABI_LIBNAME}" "c++abi")
+    set(SCRIPT_ABI_LIBNAME "c++abi")
   endif()
   # Generate a linker script inplace of a libc++.so symlink. Rerun this command
   # after cxx builds.