On Mon, Jul 11, 2022 at 02:20:18PM +0200, Thomas Schmitt wrote: > Hi, > > i wrote: > > > It appears that an argument -I is missing before /usr/include/postgresql. > > > This is a very good theory. > > Together with Greg Wooledge's observation that "make"'s macro definition > does not interpret `...` as output of shell commands we already have > two reasons why that part of the Makefile should not work. > > The riddle grows why it appears to work on Gentoo.
You're misunderstanding my conclusions. The backticks *do* work in the end, since they're passed through to the shell, and the shell interprets them the way the OP seems to want. The missing -I is probably it. It's interesting that pkg-config --cflags and pg_config --includedir deviate in this way.