Add compiler cflags error message
Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/aesni.h b/library/aesni.h
index 9e07905..93d9f0a 100644
--- a/library/aesni.h
+++ b/library/aesni.h
@@ -76,6 +76,8 @@
#elif defined(MBEDTLS_HAVE_ASM) && \
defined(__GNUC__) && defined(MBEDTLS_HAVE_X86_64)
#define MBEDTLS_AESNI_HAVE_CODE 1 // via assembly
+#elif defined(__GNUC__)
+# error "Must use `-mpclmul -msse2 -maes` for MBEDTLS_AESNI_C"
#else
#error "MBEDTLS_AESNI_C defined, but neither intrinsics nor assembly available"
#endif