Error: bad argument type - not a string: #t

        Call history:

        http-client.scm:88: chicken.string#conc
        http-client.scm:89: chicken.process-context#get-environment-variable
        http-client.scm:90: chicken.process-context#get-environment-variable
        http-client.scm:104: chicken.process-context#get-environment-variable
        http-client.scm:105: srfi-13#string-upcase
        http-client.scm:105: chicken.process-context#get-environment-variable
        http-client.scm:106: chicken.process-context#get-environment-variable
        http-client.scm:107: chicken.process-context#get-environment-variable
        http-client.scm:281: ##sys#call-with-values
        http-client.scm:281: server-connector
        http-client.scm:281: g330
        http-client.scm:254: uri-common#uri-scheme
        http-client.scm:256: ##sys#call-with-values                                                                                                                                                                                                                                            http-client.scm:257: uri-common#uri-host                                                                                                                                                                                                                                               http-client.scm:258: uri-common#uri-port                                                                                                                                                                                                                                               http-client.scm:257: ssl-connect*               <--