Re: ‘core-updates’ is back!

[Andy Wingo <wingo@igalia.com>]

On Tue 29 Aug 2017 00:01, ludo@gnu.org (Ludovic Courtès) writes:

> Yup, I just created a new ‘core-updates’ branch by pushing
> <https://bugs.gnu.org/27849>.  Enjoy!
>
> Let’s freeze in one month, say Oct. 1st?

It would be pretty cool if we could fix our O(n^2) problems in search
paths in this core-updates -- basically whenever you go to create an
environment, instead of making e.g. VAR=A:B:C:..., for all VARs
(LIBRARY_PATH, PKG_CONFIG_PATH, etc), instead we make a union directory
Z containing the union of A, B, C, etc and set VAR=Z.  The goal would be
to fix quadratic run-time lookup costs by replacing it with a
compile-time computation.  This applies to many lookups: PATH, -rpath,
etc.

For specific variables we might also have to rewrite some internal
references, for example to replace the -L line in pkg-config files to
point to the union directory.  Dunno if there are more examples or if
PKG_CONFIG_PATH is the only one.

Andy