abseil-cpp

Add ABSL_IS_TRIVIALLY_RELOCATABLE and ABSL_ATTRIBUTE_TRIVIAL_ABI macros for use with clang's __is_trivially_relocatable and [[clang::trivial_abi]].

Merge pull request #1223 from ElijahPepe:fix/implement-snprintf-safely

Fix frame pointer alignment check.

Fixed sign-conversion warning in code.

Import of CCTZ from GitHub.