Log Message:
include-what-you-use: updated to 0.16

iwyu 0.16 compatible with llvm+clang 12 is released. Major changes:

[iwyu_tool] Accept --load/-l argument for load limiting
[iwyu_tool] Signal success/failure with exit code
[mappings] Harmonize mapping generators
[mappings] Add mapping generator for CPython
[mappings] Improve mappings for libstdc++ and Boost
[cmake] Add explicit C++14 compiler flag
... and many internal improvements

iwyu 0.15 compatible with llvm+clang 11 is released. Major changes:

[iwyu] Fix crash due to undefined behavior in AST traversal
[iwyu] Improve handling of operator new including C++17 features
[iwyu] Improve handling of templates
[iwyu_tool] Remove known compiler wrappers from the command list
[mappings] Improve Qt mapping generator
[mappings] Improve boost mappings
[mappings] Improve built-in mappings for <time.h>
[mappings] Add built-in mappings for max_align_t, ptrdiff_t, and wchar_t
[cmake] Support shared LLVM/Clang libraries and other improvements