diff --git a/repos/c2sm/packages/claw/package.py b/repos/c2sm/packages/claw/package.py
index 7e17c6e301..c32769a1e8 100644
--- a/repos/c2sm/packages/claw/package.py
+++ b/repos/c2sm/packages/claw/package.py
@@ -55,6 +55,8 @@ class Claw(CMakePackage):
     # Otherwise, they are cached to the user's home directory.
     patch('ivy_local_cache.patch', when='@:2.0.3')
 
+    patch('xcodeml-tools.patch', working_dir="xcodeml-tools")
+
     # https://github.com/claw-project/claw-compiler/pull/586
     conflicts('%nag', when='@:2.0.1')
 
diff --git a/repos/c2sm/packages/claw/xcodeml-tools.patch b/repos/c2sm/packages/claw/xcodeml-tools.patch
new file mode 100644
index 0000000000..53ae3feb94
--- /dev/null
+++ b/repos/c2sm/packages/claw/xcodeml-tools.patch
@@ -0,0 +1,36 @@
+--- a/C-FrontEnd/src/c-xcodeml.c
++++ b/C-FrontEnd/src/c-xcodeml.c
+@@ -251,7 +251,8 @@ outxTag(FILE *fp, int indent, CExpr *expr, const char *tag, int xattrFlag,
+         voutxTag(fp, indent, expr, tag, xattrFlag, attrFmt, args);
+         va_end(args);
+     } else {
+-        voutxTag(fp, indent, expr, tag, xattrFlag, attrFmt, NULL);
++	va_list empty_va_list = va_list();
++        voutxTag(fp, indent, expr, tag, xattrFlag, attrFmt, empty_va_list);
+     }
+ }
+ 
+@@ -282,9 +283,10 @@ outxTagForStmt(FILE *fp, int indent, CExpr *expr, const char *tag, int addXattrF
+             attrFmt, args);
+         va_end(args);
+     } else {
++	va_list empty_va_list = va_list();
+         voutxTag(fp, indent, expr, tag,
+             XATTR_LINENO|XATTR_COMMON|addXattrFlag,
+-            attrFmt, NULL);
++            attrFmt, empty_va_list);
+     }
+ }
+ 
+@@ -301,9 +303,10 @@ outxTagForExpr(FILE *fp, int indent, CExpr *expr, const char *tag, int addXattrF
+             attrFmt, args);
+         va_end(args);
+     } else {
++	va_list empty_va_list = va_list();
+         voutxTag(fp, indent, expr, tag,
+             XATTR_TYPE|XATTR_IS_GCCEXTENSION|XATTR_COMMON|addXattrFlag,
+-            attrFmt, NULL);
++            attrFmt, empty_va_list);
+     }
+ }
+