diff --git a/mingw-w64-crt/testcases/Makefile.am b/mingw-w64-crt/testcases/Makefile.am
index 66136b8..c00111e 100644
--- a/mingw-w64-crt/testcases/Makefile.am
+++ b/mingw-w64-crt/testcases/Makefile.am
@@ -85,7 +85,8 @@
   t_swprintf0 \
   t_swprintf1 \
   t_time \
-  t_tls1 \
+  t_tls_ansi \
+  t_tls_c11 \
   t_tmpfile \
   t_towctrans \
   t_trycatch \
@@ -141,6 +142,12 @@
 # Link t_safe_flush against libprocdetach.dll
 t_safe_flush_LDADD = libprocdetach.dll
 
+# Compile t_tls_ansi in C89 mode
+t_tls_ansi_CFLAGS = -std=c89 $(AM_CFLAGS)
+
+# Compile t_tls_c11 in C11 mode
+t_tls_c11_CFLAGS = -std=c11 $(AM_CFLAGS)
+
 if ENABLE_TESTS_UNICODE
   # The following tests require compiler support for -municode option
   testcase_progs += \
diff --git a/mingw-w64-crt/testcases/t_tls_ansi.c b/mingw-w64-crt/testcases/t_tls_ansi.c
new file mode 100644
index 0000000..c8c5dbb
--- /dev/null
+++ b/mingw-w64-crt/testcases/t_tls_ansi.c
@@ -0,0 +1 @@
+#include "t_tls_c.c"
diff --git a/mingw-w64-crt/testcases/t_tls1.c b/mingw-w64-crt/testcases/t_tls_c.c
similarity index 100%
rename from mingw-w64-crt/testcases/t_tls1.c
rename to mingw-w64-crt/testcases/t_tls_c.c
diff --git a/mingw-w64-crt/testcases/t_tls_c11.c b/mingw-w64-crt/testcases/t_tls_c11.c
new file mode 100644
index 0000000..c8c5dbb
--- /dev/null
+++ b/mingw-w64-crt/testcases/t_tls_c11.c
@@ -0,0 +1 @@
+#include "t_tls_c.c"