From 9ab0fa8793c904afd658e10fb563aef7565c9f5d Mon Sep 17 00:00:00 2001
From: Brad Smith <brad@comstyle.com>
Date: Sun, 22 Mar 2026 00:44:41 -0400
Subject: [PATCH] Fix linking of libiscsi to libpthread

libiscsi utilizes a bunch of POSIX threads functions but does
not link against libpthread as it should nor the pkg-config file
properly listing libpthread as a static link time dependency.
---
 configure.ac    | 12 ++++++++++++
 lib/Makefile.am |  8 +++++++-
 libiscsi.pc.in  |  2 +-
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index 8ab9b6c..9b5e7ee 100644
--- a/configure.ac
+++ b/configure.ac
@@ -230,6 +230,18 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
 	fi
 AM_CONDITIONAL([HAVE_PTHREAD], [test x$libiscsi_cv_HAVE_PTHREAD = xyes])
 
+# check for libpthread
+if test "$libiscsi_cv_HAVE_PTHREAD" = yes; then
+  ac_save_LIBS=$LIBS
+  AC_CHECK_LIB([pthread], [pthread_spin_lock], [])
+  LIBS="$ac_save_LIBS"
+  if test "$ac_cv_lib_pthread_pthread_spin_lock" = yes; then
+    LIBS_PRIVATE="-lpthread"
+  fi
+fi
+AC_SUBST(LIBS_PRIVATE)
+AM_CONDITIONAL([HAVE_PTHREAD_SPIN_LOCKS], [test x$ac_cv_lib_pthread_pthread_spin_lock = xyes])
+
 AC_CACHE_CHECK([whether libcunit is available],
                [ac_cv_have_cunit],
                [ac_save_CFLAGS="$CFLAGS"
diff --git a/lib/Makefile.am b/lib/Makefile.am
index e016bf1..f19682c 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -21,8 +21,14 @@ if HAVE_LINUX_ISER
 libiscsipriv_la_SOURCES += iser.c
 endif
 
+libiscsipriv_la_LIBADD =
+
+if HAVE_PTHREAD_SPIN_LOCKS
+libiscsipriv_la_LIBADD += -lpthread
+endif
+
 if HAVE_LINUX_ISER
-libiscsipriv_la_LIBADD = -libverbs -lrdmacm -lpthread
+libiscsipriv_la_LIBADD += -libverbs -lrdmacm
 endif
 
 libiscsipriv_la_LDFLAGS = -no-undefined
diff --git a/libiscsi.pc.in b/libiscsi.pc.in
index 7b1fee5..504c6a4 100644
--- a/libiscsi.pc.in
+++ b/libiscsi.pc.in
@@ -8,5 +8,5 @@ Description: iSCSI initiator library
 Version: @VERSION@
 
 Libs: -L${libdir} -liscsi
-Libs.private:
+Libs.private: @LIBS_PRIVATE@
 Cflags: -I${includedir}