Depending on how the toolchain is configured or how the testsuite is
executed, -mthumb may not be compatible. Like for other tests, skip
pr97969.c in this case.

For instance arm-linux-gnueabihf and -march=armv5t in RUNTESTFLAGS.

2021-01-27  Christophe Lyon  <christophe.lyon@linaro.org>

gcc/testsuite/
PR target/97969
* gcc.target/arm/pr97969.c: Skip if thumb mode is not available.

diff --git a/gcc/testsuite/gcc.target/arm/pr97969.c
b/gcc/testsuite/gcc.target/arm/pr97969.c
index 714a1d1..0b5d07f 100644
--- a/gcc/testsuite/gcc.target/arm/pr97969.c
+++ b/gcc/testsuite/gcc.target/arm/pr97969.c
@@ -1,4 +1,5 @@
 /* { dg-do compile } */
+/* { dg-skip-if "" { ! { arm_thumb1_ok || arm_thumb2_ok } } } */
 /* { dg-options "-std=c99 -fno-omit-frame-pointer -mthumb -w -Os" } */

 typedef a[23];