Re: ns build symlinks all libexec programs into bin directory

[Jan Djärv]

Hello.

12 maj 2012 kl. 20:18 skrev Glenn Morris:

> 
> Why does a --with-ns build do this (in install-arch-dep):
> 
> cd nextstep/Emacs.app/bin
> ls -l
>    hexl -> ../libexec/hexl
>    movemail -> ../libexec/movemail
>    profile -> ../libexec/profile
>    rcs2log -> ../libexec/rcs2log
>    update-game-score -> ../libexec/update-game-score
>    vcdiff -> ../libexec/vcdiff
> 
> Ie, create symlinks to the libexec programs in the bin directory?
> 
> These programs are supposed to be for internal Emacs use only, which is
> why they get installed in libexec in the first place.

Short answer: So Emacs can find them :-)

Long answer:

The path to libexec is in PATH_EXEC epaths.h from epaths.in and then added to 
exec-path.
epaths.h is created at make time by the top level Makefile.
make install for --with-ns installs to nextstep/Emacs.app in the emacs tree.
Emacs.app can then be copied to its final place, which can be anywhere or 
another machine.
Thus, PATH_EXEC points to libexec in nextstep/Emacs.app, but when Emacs.app is 
installed (say on another machine), that values is not valid.  Hence the links 
into bin as  bin is in exec-path (derived from invocation directory and not by 
a compile time constant).

The idea is that Emacs.app is self contained and can be relocated anywhere as 
is how app-bundles are supposed to work.  A more intelligent search for libexec 
would also solve it.  For NS we know it is in the same place as bin, so we 
could just add libexec to exe-path the same way as bin.  But I guess nobody 
thought of this as a problem.

        Jan D.