bug#35590: Emacs info can't open info manuals

[sirgazil <sirgazil@zoho.com>]

---- On Sun, 05 May 2019 21:26:15 -0500 Mark H Weaver <mhw@netris.org> wrote ----

 > Hi, 
 >  
 > sirgazil <sirgazil@zoho.com> writes: 
 >  
 > > I can't open info manuals in an Emacs freshly installed in my GNU 
 > > system installed in a real machine using the ISO installer 
 > > (https://ftp.gnu.org/gnu/guix/guix-system-install-1.0.0.x86_64-linux.iso.xz). 
 > > 
 > > ## Steps to reproduce 
 > > 
 > > 1. guix install emacs 
 > > 2. Start Emacs. 
 > > 3. M-x info Enter. 
 > > 4. m Guix Enter (or any other manual). 
 > > 
 > > 
 > > ## Unexpected result 
 > > 
 > > The manual is not displayed, and the minibuffer says: 
 > > 
 > >     Uncompression program 'sh' not found 
 >  
 > This is surprising.  On a Guix system, sh is unconditionally installed 
 > in /bin/sh.  If you type M-x getenv PATH RET in Emacs, does the 
 > displayed string include /bin?  Does M-! sh RET show an error? 


M-x getenv PATH RET shows "bin"s in other paths, but not "/bin":

/gnu/store/hk4f641r18vpj44m42pny6rp1nwg3d4w-glib-2.56.3-bin/bin:/home/sirgazil/.guix-profile/bin:/home/sirgazil/.guix-profile/sbin:/run/setuid-programs:/home/sirgazil/.config/guix/current/bin:/home/sirgazil/.guix-profile/bin:/home/sirgazil/.guix-profile/sbin:/run/current-system/profile/bin:/run/current-system/profile/sbin

"/bin/sh" exists in the system, though:

    $ ls -l /bin
    total 4
    lrwxrwxrwx 1 root root 62 may  6 06:19 sh -> /gnu/store/qn1ax1fkj16x280m1rv7mcimfmn9l2pf-bash-4.4.23/bin/sh

M-! sh RET results in "command not found":

    /gnu/store/qn1ax1fkj16x280m1rv7mcimfmn9l2pf-bash-4.4.23/bin/bash: sh: no se encontró la orden