[Peter Eisentraut <peter.eisentraut@enterprisedb.com>]

macOS has traditionally used extension .dylib for shared libraries (used 
at build time) and .so for dynamically loaded modules (used by 
dlopen()).  This complicates the build system a bit.  Also, Meson uses 
.dylib for both, so it would be worth unifying this in order to be able 
to get equal build output.

There doesn't appear to be any reason to use any particular extension 
for dlopened modules, since dlopen() will accept anything and PostgreSQL 
is well-factored to be able to deal with any extension.  Other software 
packages that I have handy appear to be about 50/50 split on which 
extension they use for their plugins.  So it seems possible to change 
this safely.

Attachments:

0001-Unify-DLSUFFIX-on-Darwin.patch (text/plain, 4.0K) download
From 291defe5f2aed76c608de3894d131eafa3eaf761 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Wed, 22 Jun 2022 13:04:23 +0200
Subject: [PATCH] Unify DLSUFFIX on Darwin

macOS has traditionally used extension .dylib for shared libraries
(used at build time) and .so for dynamically loaded modules (used by
dlopen()).  This complicates the build system a bit.  Also, Meson uses
.dylib for both, so it would be worth unifying this in order to be
able to get equal build output.

There doesn't appear to be any reason to use any particular extension
for dlopened modules, since dlopen() will accept anything and
PostgreSQL is well-factored to be able to deal with any extension.
Other software packages that I have handy appear to be about 50/50
split on which extension they use for their plugins.  So it seems
possible to change this safely.
---
 config/python.m4              | 15 +++++----------
 configure                     | 15 +++++----------
 src/Makefile.shlib            |  2 --
 src/makefiles/Makefile.darwin |  2 +-
 src/template/darwin           |  2 ++
 5 files changed, 13 insertions(+), 23 deletions(-)

diff --git a/config/python.m4 b/config/python.m4
index e500873ff3..b295ad3d3a 100644
--- a/config/python.m4
+++ b/config/python.m4
@@ -120,16 +120,11 @@ else
 	found_shlib=0
 	for d in "${python_libdir}" "${python_configdir}" /usr/lib64 /usr/lib
 	do
-		# Note: DLSUFFIX is for loadable modules, not shared
-		# libraries, so cannot be used here portably.  Just
-		# check all known possibilities.
-		for e in .so .dll .dylib .sl; do
-			if test -e "$d/lib${ldlibrary}$e"; then
-				python_libdir="$d"
-				found_shlib=1
-				break 2
-			fi
-		done
+		if test -e "$d/lib${ldlibrary}${DLSUFFIX}"; then
+			python_libdir="$d"
+			found_shlib=1
+			break 2
+		fi
 	done
 	# Some platforms (OpenBSD) require us to accept a bare versioned shlib
 	# (".so.n.n") as well. However, check this only after failing to find
diff --git a/configure b/configure
index 7dec6b7bf9..f8306a2999 100755
--- a/configure
+++ b/configure
@@ -10570,16 +10570,11 @@ else
 	found_shlib=0
 	for d in "${python_libdir}" "${python_configdir}" /usr/lib64 /usr/lib
 	do
-		# Note: DLSUFFIX is for loadable modules, not shared
-		# libraries, so cannot be used here portably.  Just
-		# check all known possibilities.
-		for e in .so .dll .dylib .sl; do
-			if test -e "$d/lib${ldlibrary}$e"; then
-				python_libdir="$d"
-				found_shlib=1
-				break 2
-			fi
-		done
+		if test -e "$d/lib${ldlibrary}${DLSUFFIX}"; then
+			python_libdir="$d"
+			found_shlib=1
+			break 2
+		fi
 	done
 	# Some platforms (OpenBSD) require us to accept a bare versioned shlib
 	# (".so.n.n") as well. However, check this only after failing to find
diff --git a/src/Makefile.shlib b/src/Makefile.shlib
index 551023c6fb..d0ec325bf1 100644
--- a/src/Makefile.shlib
+++ b/src/Makefile.shlib
@@ -118,7 +118,6 @@ endif
 ifeq ($(PORTNAME), darwin)
   ifdef soname
     # linkable library
-    DLSUFFIX		= .dylib
     ifneq ($(SO_MAJOR_VERSION), 0)
       version_link	= -compatibility_version $(SO_MAJOR_VERSION) -current_version $(SO_MAJOR_VERSION).$(SO_MINOR_VERSION)
     endif
@@ -127,7 +126,6 @@ ifeq ($(PORTNAME), darwin)
     shlib_major		= lib$(NAME).$(SO_MAJOR_VERSION)$(DLSUFFIX)
   else
     # loadable module
-    DLSUFFIX		= .so
     LINK.shared		= $(COMPILER) -bundle -multiply_defined suppress
   endif
   BUILD.exports		= $(AWK) '/^[^\#]/ {printf "_%s\n",$$1}' $< >$@
diff --git a/src/makefiles/Makefile.darwin b/src/makefiles/Makefile.darwin
index 4fc81c1584..45f253a5b4 100644
--- a/src/makefiles/Makefile.darwin
+++ b/src/makefiles/Makefile.darwin
@@ -10,5 +10,5 @@ else
 endif
 
 # Rule for building a shared library from a single .o file
-%.so: %.o
+%$(DLSUFFIX): %.o
 	$(CC) $(CFLAGS) $< $(LDFLAGS) $(LDFLAGS_SL) -bundle $(BE_DLLLIBS) -o $@
diff --git a/src/template/darwin b/src/template/darwin
index e14d53b601..fd30e19b6a 100644
--- a/src/template/darwin
+++ b/src/template/darwin
@@ -55,3 +55,5 @@ case $host_os in
     USE_SYSV_SEMAPHORES=1
     ;;
 esac
+
+DLSUFFIX=".dylib"
-- 
2.36.1