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. ---------------------------------------------------------------------- info make shows a "MAKE(P) POSIX Programmer's Manual" which explains that what i perceive as variables are indeed macros. No mentioning is to see of any shell-like properties. The web has workarounds with GNU make: https://stackoverflow.com/questions/10024279/how-to-use-shell-commands-in-makefile This is confirmed by https://www.gnu.org/software/make/manual/html_node/Shell-Function.html Alternatively i would try to hand over the "-I..." argument by an environment variable. But i guess the autotools way is to insert the desired arguments at latest when ./configure creates Makefile from Makefile.in. (Now we could need hearsay about how this is to be done ...) Have a nice day :) Thomas