From 6e5dc7374cefc2fbade06582fb56b45126c97b9b Mon Sep 17 00:00:00 2001
From: Erik Schnetter <schnetter@gmail.com>
Date: Mon, 12 Sep 2022 14:17:49 -0400
Subject: [PATCH] openblas: Allow building linktest.c with clang@15 (#32597)

---
 .../builtin/packages/openblas/linktest.patch  | 21 +++++++++++++++++++
 .../builtin/packages/openblas/package.py      |  4 ++++
 2 files changed, 25 insertions(+)
 create mode 100644 var/spack/repos/builtin/packages/openblas/linktest.patch

diff --git a/var/spack/repos/builtin/packages/openblas/linktest.patch b/var/spack/repos/builtin/packages/openblas/linktest.patch
new file mode 100644
index 00000000000..6ec5f7fff86
--- /dev/null
+++ b/var/spack/repos/builtin/packages/openblas/linktest.patch
@@ -0,0 +1,21 @@
+--- a/exports/gensymbol
++++ b/exports/gensymbol
+@@ -3914,6 +3914,18 @@
+     @underscore_objs = (@underscore_objs, @misc_common_objs);
+     @no_underscore_objs = (@no_underscore_objs, @misc_common_objs);
+ 
++    foreach $objs (@underscore_objs) {
++        print "void ", $symbolprefix, $objs, $bu, $symbolsuffix, "();\n" if $objs ne "xerbla";
++    }
++
++    foreach $objs (@need_2underscore_objs) {
++        print "void ", $symbolprefix, $objs, $bu, $bu, $symbolsuffix, "();\n";
++    }
++
++    foreach $objs (@no_underscore_objs) {
++        print "void ", $symbolprefix, $objs, $symbolsuffix, "();\n";
++    }
++
+     print "int main(void){\n";
+     foreach $objs (@underscore_objs) {
+         print $symbolprefix, $objs, $bu, $symbolsuffix, "();\n" if $objs ne "xerbla";
diff --git a/var/spack/repos/builtin/packages/openblas/package.py b/var/spack/repos/builtin/packages/openblas/package.py
index c1ac5ac24e4..b8a0d16d5ae 100644
--- a/var/spack/repos/builtin/packages/openblas/package.py
+++ b/var/spack/repos/builtin/packages/openblas/package.py
@@ -153,6 +153,10 @@ class Openblas(MakefilePackage):
     # Use /usr/bin/env perl in build scripts
     patch("0001-use-usr-bin-env-perl.patch", when="@:0.3.13")
 
+    # Declare external functions in linktest
+    # See <https://github.com/xianyi/OpenBLAS/issues/3760>
+    patch("linktest.patch", when="@0.3.20")
+
     # See https://github.com/spack/spack/issues/19932#issuecomment-733452619
     conflicts("%gcc@7.0.0:7.3,8.0.0:8.2", when="@0.3.11:")