Don't do that. Please.

[AltGr]

operf-macro/lib/macroperf.ml

Lines 196 to 206 in f0e21ad

	let cur_switch ~opamroot =
	let rex = Re_pcre.regexp "switch: \"([^\"]*)\"" in
	let config_lines = File.lines_of_file @@ Opt.default root opamroot / "config" in
	List.fold_left
	(fun a l ->
	try
	let substrings = Re_pcre.exec ~rex l in
	Re_pcre.get_substring substrings 1
	with _ -> a
	)
	"" config_lines

Either use the opam lib, or ensure to follow the exact semantics. I.e. respect the OPAMSWITCH and similar variables.

What happens if operf-macro is run without proper eval $(opam config env) ?