Operating system: Ubuntu 16.04.5 LTS \n \l
Hardware platform: x86-64
C Compiler: gcc (Ubuntu 5.4.0-6ubuntu1~16.04.10) 5.4.0 20160609
Installation works?: yes
Tests work?: yes
Installation of eggs works?: no

$ make PLATFORM=linux PREFIX="$HOME/programs/$(basename "$PWD")" install check

This doesn't work for rc1 either:

$ ~/programs/chicken-5.0.0rc2/bin/chicken-install pastiche
Server error:

Error: [Server] no such extension or version
"pastiche"
#f
Server error:

Error: [Server] no such extension or version
"pastiche"
#f

Error: extension or version not found: "pastiche"

$ cat ~/programs/chicken-5.0.0rc2/share/chicken/setup.defaults 
;;;; setup.defaults - defaults for chicken-install -*- Scheme -*-


;; version-number of the defaults file - checked by "chicken-install"
;  when defaults are loaded

(version 2)


;; list of locations (eggs stored in the local fileystem)
;
; (location DIRECTORY ...)
;
; Note that these override eggs from servers.


;; list of servers in the order in which they will be processed
;
; (server URL ...)
;
; URL may be an alias (see below) or a real URL.

(server "kitten-technologies")
(server "call-cc")


;; extensions-mappings
;
; (map (EXTENSIONNAME ... -> OTHEREXTENSIONNAME ...))

(map
(data-structures 
extras files foreign irregex lolevel ports tcp
posix irregex srfi-4
->) )


;; aliases for servers
;
; (alias (NAME REALNAME) ...)

(alias 
("call-cc" "http://code.call-cc.org/cgi-bin/henrietta.cgi")
("kitten-technologies" "http://chicken.kitten-technologies.co.uk/henrietta.cgi"))


;; overrides
;
; (override (NAME VERSION) ...)
;
; or:
;
; (override FILENAME)


;; hack
;
; (hack EXPR)
;
;   EXPR should evaluate to a procedure of the type, where the 
;   procedure is of type EGGNAME DEPENDENCIES -> DEPENDENCIES' and
;   may modify the dependencies-list of an arbitrary egg. All
;   hack procedures are invoked in the order given here