From 7d3502b5003ad54903b7a9e9aec5a853dfbe0221 Mon Sep 17 00:00:00 2001
From: Andrew <16061801+brada4@users.noreply.github.com>
Date: Tue, 6 Nov 2018 08:20:55 +0000
Subject: [PATCH] Add -frecursive gfortran option by default

---
 Makefile.rule   | 4 ++--
 Makefile.system | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/Makefile.rule b/Makefile.rule
index 6522b0777..d97607f2e 100644
--- a/Makefile.rule
+++ b/Makefile.rule
@@ -192,8 +192,8 @@ NO_AFFINITY = 1
 # Flags for POWER8 are defined in Makefile.power. Don't modify COMMON_OPT
 # COMMON_OPT = -O2
 
-# gfortran option for LAPACK
-# enable this flag only on 64bit Linux and if you need a thread safe lapack library
+# gfortran option for LAPACK to improve thread-safety
+# It is enabled by default in Makefile.system for gfortran
 # Flags for POWER8 are defined in Makefile.power. Don't modify FCOMMON_OPT
 # FCOMMON_OPT = -frecursive
 
diff --git a/Makefile.system b/Makefile.system
index b4cd4222a..8de0b8f6e 100644
--- a/Makefile.system
+++ b/Makefile.system
@@ -718,6 +718,8 @@ endif
 ifeq ($(F_COMPILER), GFORTRAN)
 CCOMMON_OPT += -DF_INTERFACE_GFORT
 FCOMMON_OPT += -Wall
+# make single-threaded LAPACK calls thread-safe #1847
+FCOMMON_OPT += -frecursive
 #Don't include -lgfortran, when NO_LAPACK=1 or lsbcc
 ifneq ($(NO_LAPACK), 1)
 EXTRALIB += -lgfortran