Josh Berdine 31dd2884f6 [sledge] Use a cookie instead of env var to enable ppx_trace ... Summary: Passing info that affects the build through environment variables is bad since it is not very visible, e.g. in log files. Also, those settings are not recorded in .merlin files, leading to merlin using the default configuration. This diff changes ppx_trace to use a 'cookie' instead of an environment variable, and configures dune to set this cookie based on the selected profile. This has the benefit of using command line arguments such as `--cookie 'ppx_trace_enabled="1"'` which appear in build logs and .merlin files. Reviewed By: jvillard Differential Revision: D20590515 fbshipit-source-id: d2daceaa3		5 years ago
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dune	[sledge] Use a cookie instead of env var to enable ppx_trace	5 years ago