PostGIS vs. PGXS in 9.0beta3

Hackers,

A 9.0b3 tester reported this issue with our single most popular
PostgreSQL extension, PostGIS:

==================
Postgis makes use of 'PGXS' in postgresql > 8.2. Within postgresql-9,
datadir and many other variables are defined as multiple values with an
append operator, like this:

$ grep -i datadir /usr/pgsql-9.0/lib/pgxs/src/Makefile.global
[snip]
datadir := /usr/pgsql-9.0/share

Postgis-1.5.1's Makefile.pgxs makefile override tries to use datadir as
a flat variable, doesn't try to expand the array-like structure with a
for loop or similar. So when 'make install' within postgis-1.5
configured against pgsql-9.x is ran, 'make' treats the second value
within DATADIR as a command it should just run, which fails:

http://postgis.refractions.net/pipermail/postgis-users/2010-May/026654.html

I've tried the latest tarball SVN exports of both postgis-1.5.x and
postgis-2.x without success.
==================

I'm unsure of what the resolution of this issue should be ... it seems
like the fix belongs in PostGIS ... but I also think we can't go final
until this is resolved, given.

--
-- Josh Berkus
PostgreSQL Experts Inc.
http://www.pgexperts.com