This should fix the build on s390x.

2669.patch

@@ -0,0 +1,89 @@
+From a2d13ea61183099c05aa31e23ef59e1411d77177 Mon Sep 17 00:00:00 2001
+From: Marius Hillenbrand <mhillen@linux.ibm.com>
+Date: Tue, 16 Jun 2020 14:40:50 +0200
+Subject: [PATCH 1/2] Fix gcc version detection for zarch
+
+Employ common variables for gcc version detection and fix the broken
+check for gcc >= 5.2.
+Fixes #2668
+
+Signed-off-by: Marius Hillenbrand <mhillen@linux.ibm.com>
+---
+ Makefile.system | 19 ++++++++++++++-----
+ 1 file changed, 14 insertions(+), 5 deletions(-)
+
+diff --git a/Makefile.system b/Makefile.system
+index 8d78b420f..5738b14ec 100644
+--- a/Makefile.system
++++ b/Makefile.system
+@@ -282,9 +282,11 @@ endif
+ ifeq ($(C_COMPILER), GCC)
+ GCCVERSIONGTEQ4 := $(shell expr `$(CC) -dumpversion | cut -f1 -d.` \>= 4)
+ GCCVERSIONGT4 := $(shell expr `$(CC) -dumpversion | cut -f1 -d.` \> 4)
++GCCVERSIONEQ5 := $(shell expr `$(CC) -dumpversion | cut -f1 -d.` = 5)
+ GCCVERSIONGT5 := $(shell expr `$(CC) -dumpversion | cut -f1 -d.` \> 5)
+ GCCVERSIONGTEQ7 := $(shell expr `$(CC) -dumpversion | cut -f1 -d.` \>= 7)
+ GCCVERSIONGTEQ9 := $(shell expr `$(CC) -dumpversion | cut -f1 -d.` \>= 9)
++GCCMINORVERSIONGTEQ2 := $(shell expr `$(CC) -dumpversion | cut -f2 -d.` \>= 2)
+ GCCMINORVERSIONGTEQ7 := $(shell expr `$(CC) -dumpversion | cut -f2 -d.` \>= 7)
+ endif
+ 
+@@ -570,20 +572,27 @@ ifeq ($(ARCH), zarch)
+ DYNAMIC_CORE = ZARCH_GENERIC
+ 
+ # Z13 is supported since gcc-5.2, gcc-6, and in RHEL 7.3 and newer
+-GCC_GE_52 := $(subst 0,,$(shell expr `$(CC) -dumpversion` \>= "5.2"))
++ifeq ($(GCCVERSIONGT5), 1)
++	ZARCH_SUPPORT_Z13 := 1
++else ifeq ($(GCCVERSIONEQ5), 1)
++ifeq ($(GCCMINORVERSIONGTEQ2), 1)
++	ZARCH_SUPPORT_Z13 := 1
++endif
++endif
+ 
+ ifeq ($(wildcard /etc/redhat-release), /etc/redhat-release)
+-RHEL_WITH_Z13 := $(subst 0,,$(shell source /etc/os-release ; expr $$VERSION_ID \>= "7.3"))
++ifeq ($(shell source /etc/os-release ; expr $$VERSION_ID \>= "7.3"), 1)
++	ZARCH_SUPPORT_Z13 := 1
++endif
+ endif
+ 
+-ifeq ($(or $(GCC_GE_52),$(RHEL_WITH_Z13)), 1)
++ifeq ($(ZARCH_SUPPORT_Z13), 1)
+ DYNAMIC_CORE += Z13
+ else
+ $(info OpenBLAS: Not building Z13 kernels because gcc is older than 5.2 or 6.x)
+ endif
+ 
+-GCC_MAJOR_GE_7 := $(shell expr `$(CC) -dumpversion | cut -f1 -d.` \>= 7)
+-ifeq ($(GCC_MAJOR_GE_7), 1)
++ifeq ($(GCCVERSIONGTEQ7), 1)
+ DYNAMIC_CORE += Z14
+ else
+ $(info OpenBLAS: Not building Z14 kernels because gcc is older than 7.x)
+
+From 23892917667d87072eef2f18b6120f5d3c029f90 Mon Sep 17 00:00:00 2001
+From: Marius Hillenbrand <mhillen@linux.ibm.com>
+Date: Tue, 16 Jun 2020 14:45:09 +0200
+Subject: [PATCH 2/2] Makefile.system: remove duplicate variable GCCVERSIONGT5
+
+... to bring unified gcc version detection with common variables to the
+one remaining spot in Makefile.system.
+
+Signed-off-by: Marius Hillenbrand <mhillen@linux.ibm.com>
+---
+ Makefile.system | 1 -
+ 1 file changed, 1 deletion(-)
+
+diff --git a/Makefile.system b/Makefile.system
+index 5738b14ec..63cdbccd8 100644
+--- a/Makefile.system
++++ b/Makefile.system
+@@ -606,7 +606,6 @@ ifneq ($(C_COMPILER), GCC)
+ DYNAMIC_CORE += POWER9
+ endif
+ ifeq ($(C_COMPILER), GCC)
+-GCCVERSIONGT5 := $(shell expr `$(CC) -dumpversion | cut -f1 -d.` \> 5)
+ ifeq ($(GCCVERSIONGT5), 1)
+ DYNAMIC_CORE += POWER9
+ else

openblas.spec

@@ -29,6 +29,9 @@ Patch2:         openblas-0.2.15-constructor.patch
 # Supply the proper flags to the test makefile
 Patch3:         openblas-0.3.7-tests.patch
 
+# Fix broken detection for z13 support
+Patch4:         https://patch-diff.githubusercontent.com/raw/xianyi/OpenBLAS/pull/2669.patch
+
 BuildRequires:  gcc
 BuildRequires:  gcc-c++
 BuildRequires:  gcc-gfortran
@@ -241,6 +244,7 @@ cd OpenBLAS-%{version}
 %patch2 -p1 -b .constructor
 %endif
 %patch3 -p1 -b .tests
+%patch4 -p1 -b .s390x
 
 # Fix source permissions
 find -name \*.f -exec chmod 644 {} \;
@@ -380,7 +384,7 @@ TARGET="TARGET=POWER8 DYNAMIC_ARCH=1 DYNAMIC_OLDER=1"
 TARGET="TARGET=ARMV8 DYNAMIC_ARCH=1 DYNAMIC_OLDER=1"
 %endif
 %ifarch s390x
-TARGET="TARGET=ZARCH_GENERIC DYNAMIC_ARCH=1"
+TARGET="TARGET=ZARCH_GENERIC DYNAMIC_ARCH=1 DYNAMIC_OLDER=1"
 %endif
 
 %if 0%{?rhel} == 5