Fix MSan build without MBEDTLS_TIMING_C
When MBEDTLS_TIMING_C was not defined in config.h, but the MemSan
memory sanitizer was activated, entropy_poll.c used memset without
declaring it. Fix this by including string.h unconditionally.
#include MBEDTLS_CONFIG_FILE
#endif
+#include <string.h>
+
#if defined(MBEDTLS_ENTROPY_C)
#include "mbedtls/entropy.h"
#include "mbedtls/entropy_poll.h"
#if defined(MBEDTLS_TIMING_C)
-#include <string.h>
#include "mbedtls/timing.h"
#endif
#if defined(MBEDTLS_HAVEGE_C)
