Summary:
In this chage we add support for the string-based configuration
mechanism for configuring FDR mode.
We deprecate most of the `xray_fdr_log_*` flags that are set with the
`XRAY_OPTIONS` environment variable. Instead we make the FDR
implementation take defaults from the `XRAY_FDR_OPTIONS` environment
variable, and use the flags defined in `xray_fdr_flags.{h,cc,inc}` for
the options we support.
This change addresses http://llvm.org/PR36790.
Depends on D46173.
Reviewers: eizan, pelikan, kpw, echristo
Subscribers: llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D46174
llvm-svn: 331506