diff --git a/changes/bug22838_028 b/changes/bug22838_028
new file mode 100644
index 0000000000..1d0a4fbfd1
--- /dev/null
+++ b/changes/bug22838_028
@@ -0,0 +1,5 @@
+  o Minor bugfixes (compilation, mingw, backport from 0.3.1.1-alpha):
+    - Backport a fix for an "unused variable" warning that appeared
+      in some versions of mingw. Fixes bug 22838; bugfix on
+      0.2.8.1-alpha.
+
diff --git a/src/test/test_switch_id.c b/src/test/test_switch_id.c
index 322f5bdc7a..e12205bb2e 100644
--- a/src/test/test_switch_id.c
+++ b/src/test/test_switch_id.c
@@ -79,6 +79,7 @@ main(int argc, char **argv)
 #if defined(_WIN32)
   (void) argc;
   (void) argv;
+  (void) which_test;
 
   fprintf(stderr, "This test is not supported on your OS.\n");
   return 77;