Be more explicit about the need for -fno-rtti

skeleton/CMakeLists.txt

@@ -6,7 +6,8 @@ add_library(SkeletonPass MODULE
 # Use C++11 to compile our pass (i.e., supply -std=c++11).
 target_compile_features(SkeletonPass PRIVATE cxx_range_for cxx_auto_type)
 
-# LLVM is (typically) built with no C++ RTTI. We need to match that.
+# LLVM is (typically) built with no C++ RTTI. We need to match that;
+# otherwise, we'll get linker errors about missing RTTI data.
 set_target_properties(SkeletonPass PROPERTIES
     COMPILE_FLAGS "-fno-rtti"
 )