From fa7cbf82221f81efb59fcba0ed0f80b7a2a2158a Mon Sep 17 00:00:00 2001
From: Alyssa Ross <hi@alyssa.is>
Date: Mon, 17 May 2021 17:08:57 +0000
Subject: [PATCH] Only link with libdl on Linux

Linux is (as far as I know) the only mainstream operating system that
requires linking with libdl for dlopen.  On BSD, libdl doesn't exist,
so on non-FreeBSD BSDs linking will currently fail.  On macOS, it's
apparently just a symlink to libSystem (macOS libc), presumably
present for compatibility with things that assume Linux.

So the right thing to do here is to only add -ldl on Linux, not to add
it for everything that isn't FreeBSD.

(cherry picked from commit c57ab1768767ca4f860ce5ca5faf54a7dba4969f)
---
 src/libexpr/local.mk  | 2 +-
 src/libstore/local.mk | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/libexpr/local.mk b/src/libexpr/local.mk
index ccd5293e4..00d6d75c1 100644
--- a/src/libexpr/local.mk
+++ b/src/libexpr/local.mk
@@ -9,7 +9,7 @@ libexpr_SOURCES := $(wildcard $(d)/*.cc) $(wildcard $(d)/primops/*.cc) $(d)/lexe
 libexpr_LIBS = libutil libstore
 
 libexpr_LDFLAGS =
-ifneq ($(OS), FreeBSD)
+ifeq ($(OS), Linux)
  libexpr_LDFLAGS += -ldl
 endif
 
diff --git a/src/libstore/local.mk b/src/libstore/local.mk
index d690fea28..bc665f2cb 100644
--- a/src/libstore/local.mk
+++ b/src/libstore/local.mk
@@ -9,7 +9,7 @@ libstore_SOURCES := $(wildcard $(d)/*.cc $(d)/builtins/*.cc)
 libstore_LIBS = libutil
 
 libstore_LDFLAGS = $(SQLITE3_LIBS) -lbz2 $(LIBCURL_LIBS) $(SODIUM_LIBS) -pthread
-ifneq ($(OS), FreeBSD)
+ifeq ($(OS), Linux)
  libstore_LDFLAGS += -ldl
 endif