On FreeBSD patching is painless if you install GNU/MIT Scheme from ports.
Save this file as /usr/ports/lang/mit-scheme/files/patch-runtime_http-syntax.scm
--- runtime/http-syntax.scm.orig 2018-10-21 22:30:12 UTC
+++ runtime/http-syntax.scm
@@ -1310,8 +1310,13 @@ USA.
write-entity-tag)
(define-header "Location"
- (direct-parser parse-absolute-uri)
- absolute-uri?
+ (direct-parser
+ (*parser
+ (alt parse-absolute-uri
+ parse-relative-uri)))
+ (lambda (value)
+ (and (uri? value)
+ (not (uri-fragment value))))
write-uri)
#;
(define-header "Proxy-Authenticate"Then conmpile and install as usual
cd /usr/ports/lang/mit-scheme
make
make install