chicken-install is broken when TMPDIR=./

[Ivan Raikov]

If the environment variable TMPDIR is set to ./ then chicken-install is unable to install eggs:

TMPDIR=./ chicken-install -debug datatype

(snip)
reading files ...
  ./datatype.meta
  ./datatype.scm
  ./datatype.setup
 datatype located at ./temp72ca.9084/datatype
checking platform for `datatype' ...
checking dependencies for `datatype' ...
install order:
("datatype")
installing datatype:1.4 ...
changing current directory to ./temp72ca.9084/datatype
  '/home/igr/bin/chicken/bin/csi' -bnq -setup-mode -e "(require-library setup-api)" -e "(import setup-api)" -e "(extension-name-and-version '(\"datatype\" \"1.4\"))" 'temp72ca.9084/datatype/datatype.setup'

Error: (open-input-file) cannot open file - No such file or directory: "temp72ca.9084/datatype/datatype.setup"

	Call history:

	setup-api.scm:582: ->string	  
	setup-api.scm:583: ensure-string	  
	setup-api.scm:582: ->string	  
	setup-api.scm:645: user-install-setup	  
	<syntax>	  (import setup-api)
	<syntax>	  (import scheme chicken foreign irregex utils posix ports extras data-structures srfi-1 srfi-13 files......
	<syntax>	  (##core#undefined)
	<syntax>	  (##core#undefined)
	<syntax>	  (extension-name-and-version (quote ("datatype" "1.4")))
	<syntax>	  (quote ("datatype" "1.4"))
	<syntax>	  (##core#quote ("datatype" "1.4"))
	<eval>	  (extension-name-and-version (quote ("datatype" "1.4")))
	setup-api.scm:583: ensure-string	  
	setup-api.scm:582: ->string	  
	setup-api.scm:583: ensure-string	  
	setup-api.scm:582: ->string	  	<--


Error: shell command terminated with nonzero exit code
17920
"'/home/igr/bin/chicken/bin/csi' -bnq -setup-mode -e \"(require-library setup-ap...

[sjamaan]

IIUC this is a regression, so this ought to be fixed before we release 4.9.0. Updating milestone to reflect this.