Tom Lane a644f5fc66 Don't put library-supplied -L/-I switches before user-supplied ones. For many optional libraries, we extract the -L and -l switches needed to link the library from a helper program such as llvm-config. In some cases we put the resulting -L switches into LDFLAGS ahead of -L switches specified via --with-libraries. That risks breaking the user's intention for --with-libraries. It's not such a problem if the library's -L switch points to a directory containing only that library, but on some platforms a library helper may "helpfully" offer a switch such as -L/usr/lib that points to a directory holding all standard libraries. If the user specified --with-libraries in hopes of overriding the standard build of some library, the -L/usr/lib switch prevents that from happening since it will come before the user-specified directory. To fix, avoid inserting these switches directly into LDFLAGS during configure, instead adding them to LIBDIRS or SHLIB_LINK. They will still eventually get added to LDFLAGS, but only after the switches coming from --with-libraries. The same problem exists for -I switches: those coming from --with-includes should appear before any coming from helper programs such as llvm-config. We have not heard field complaints about this case, but it seems certain that a user attempting to override a standard library could have issues. The changes for this go well beyond configure itself, however, because many Makefiles have occasion to manipulate CPPFLAGS to insert locally-desirable -I switches, and some of them got it wrong. The correct ordering is any -I switches pointing at within-the- source-tree-or-build-tree directories, then those from the tree-wide CPPFLAGS, then those from helper programs. There were several places that risked pulling in a system-supplied copy of libpq headers, for example, instead of the in-tree files. (Commit `cb36f8ec2` fixed one instance of that a few months ago, but this exercise found more.) The Meson build scripts may or may not have any comparable problems, but I'll leave it to someone else to investigate that. Reported-by: Charles Samborski <demurgos@demurgos.net> Author: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/70f2155f-27ca-4534-b33d-7750e20633d7@demurgos.net Backpatch-through: 13		2 months ago
config	Don't put library-supplied -L/-I switches before user-supplied ones.	2 months ago
contrib	Fix incompatibility with libxml2 >= 2.14	2 months ago
doc	Clarify documentation for the initcap function	2 months ago
src	Don't put library-supplied -L/-I switches before user-supplied ones.	2 months ago
.cirrus.star	Remove duplicate words in docs and code comments.	2 years ago
.cirrus.tasks.yml	ci: Upgrade FreeBSD image	6 months ago
.cirrus.yml	ci: Make compute resources for CI configurable	2 years ago
.dir-locals.el	Make Emacs perl-mode indent more like perltidy.	7 years ago
.editorconfig	Add .editorconfig	6 years ago
.git-blame-ignore-revs	Add commit `7229ebe011` to .git-blame-ignore-revs.	1 year ago
.gitattributes	Exclude LLVM files from whitespace checks	10 months ago
.gitignore	Update top-level .gitignore.	3 years ago
COPYRIGHT	Align organization wording in copyright statement	4 months ago
GNUmakefile.in	Allow selecting the git revision to be packaged by "make dist".	1 year ago
HISTORY	Canonicalize some URLs	6 years ago
Makefile	Adapt REL_17_STABLE to its new status as a stable branch	1 year ago
README.md	Adapt REL_17_STABLE to its new status as a stable branch	1 year ago
aclocal.m4	autoconf: Move export_dynamic determination to configure	3 years ago
configure	Don't put library-supplied -L/-I switches before user-supplied ones.	2 months ago
configure.ac	Don't put library-supplied -L/-I switches before user-supplied ones.	2 months ago
meson.build	meson: Fix meson warning	3 months ago
meson_options.txt	Allow selecting the git revision to be packaged by "make dist".	1 year ago

README.md

PostgreSQL Database Management System

This directory contains the source code distribution of the PostgreSQL database management system.

PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.

General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/17/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/17/installation.html.

The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.