type t = private {cudf_file : string option;solver_timeout : float;external_solver : OpamTypes.arg list option Lazy.t;solver_preferences_default : string Lazy.t option;solver_preferences_upgrade : string Lazy.t option;solver_preferences_fixup : string Lazy.t option;
}type 'a options_fun =
?cudf_file:string option ->
?solver_timeout:float ->
?external_solver:OpamTypes.arg list option Lazy.t ->
?solver_preferences_default:string Lazy.t option ->
?solver_preferences_upgrade:string Lazy.t option ->
?solver_preferences_fixup:string Lazy.t option ->
unit ->
'aval external_solver_command :
input:string ->
output:string ->
criteria:string ->
string list option