From 14c09425054fc53ed357a56c615d4aea15d96d9e Mon Sep 17 00:00:00 2001
From: Seth R Johnson <johnsonsr@ornl.gov>
Date: Thu, 10 Feb 2022 07:33:09 -0500
Subject: [PATCH] Preserve thread_local for brace-enclosed extern "C"

---
 Source/CParse/parser.y | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/Source/CParse/parser.y b/Source/CParse/parser.y
index 2fd81ad9d..35415bb28 100644
--- a/Source/CParse/parser.y
+++ b/Source/CParse/parser.y
@@ -3133,15 +3133,22 @@ c_declaration   : c_decl {
 		    Setattr($$,"name",$2);
 		    appendChild($$,n);
 		    while (n) {
-		      if (!Equal(Getattr(n, "storage"), "typedef")) {
+		      String *s = Getattr(n, "storage");
+		      if (s) {
+			if (Strstr(s, "thread_local")) {
+			  Insert(s,0,"externc ");
+			} else if (!Equal(s, "typedef")) {
+			  Setattr(n,"storage","externc");
+			}
+		      } else {
 			Setattr(n,"storage","externc");
 		      }
 		      n = nextSibling(n);
 		    }
 		  } else {
-            if (!Equal($2,"C++")) {
+		    if (!Equal($2,"C++")) {
 		      Swig_warning(WARN_PARSE_UNDEFINED_EXTERN,cparse_file, cparse_line,"Unrecognized extern type \"%s\".\n", $2);
-            }
+		    }
 		    $$ = new_node("extern");
 		    Setattr($$,"name",$2);
 		    appendChild($$,firstChild($5));