Add work-around for non-C99 compilers
diff --git a/library/sha256.c b/library/sha256.c
index 5551140..91d461c 100644
--- a/library/sha256.c
+++ b/library/sha256.c
@@ -49,6 +49,11 @@
#endif /* MBEDTLS_PLATFORM_C */
#endif /* MBEDTLS_SELF_TEST */
+#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
+ !defined(inline) && !defined(__cplusplus)
+#define inline __inline
+#endif
+
#define SHA256_VALIDATE_RET(cond) \
MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_SHA256_BAD_INPUT_DATA )
#define SHA256_VALIDATE(cond) MBEDTLS_INTERNAL_VALIDATE( cond )