I said:
> Looks like we need some double quotes in that there ln -s command.
Sure enough, you can build in a directory whose path contains spaces
after addition of double quotes to src/backend/Makefile's ln -s
command for parse.h.
However, I found that a lot of things blow up if you try to specify
an installation prefix that contains spaces in the pathname.
configure itself failed to cope with "--prefix=/path/with/spaces",
for reasons that aren't very clear to me. I gave up when I found that
initdb couldn't deal with spaces in $PATH. There might be other
problems further downstream.
Cleaning this up might be a project for some future hacker, but I
haven't got time for it now...
regards, tom lane