gn build: Update TODO now that libcxx libcxxabi libunwind clang-tools-extra are done

Differential Revision: https://reviews.llvm.org/D61468

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@360056 91177308-0d34-0410-b5e6-96231b3b80d8

Author: nico

utils/gn/TODO.txt

@@ -1,7 +1,6 @@
 Ideas for things to do:
 
-- more projects (compiler-rt libcxx libcxxabi libunwind clang-tools-extra lldb)
-  - phosek expressed interest in compiler-rt libcxx libcxxabi libunwind
+- more projects (compiler-rt's asan/ubsan/msan/tsan, lldb)
   - once there are more projects, have an llvm_enable_projects arg, modeled
     after llvm_targets_to_build in the GN build
   - a check-all build target that runs test of all projects