This adds an alias for llvm-symbolizer with different defaults so that
it can be used as a drop-in replacement for GNU's addr2line.
If a substring "addr2line" is found in the tool's name:
* it defaults "-i", "-f" and "-C" to OFF;
* it uses "--output-style=GNU" by default.
Differential Revision: https://reviews.llvm.org/D60067
llvm-svn: 358749
