Work around MSVC bug with duplicate static declarations
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/psa_crypto_random_impl.h b/library/psa_crypto_random_impl.h
index 3b8e3ec..3c4c09a 100644
--- a/library/psa_crypto_random_impl.h
+++ b/library/psa_crypto_random_impl.h
@@ -125,8 +125,18 @@
} mbedtls_psa_random_context_t;
/* Defined in include/mbedtls/psa_util.h so that it's visible to
- * application code. */
+ * application code. The declaration here is redundant, but included
+ * as a safety net to make it more likely that a future change that
+ * accidentally causes the implementation to diverge from the interface
+ * will be noticed. */
+/* Do not include the declaration under MSVC because it doesn't accept it
+ * ("error C2370: 'mbedtls_psa_get_random' : redefinition; different storage class").
+ * Observed with Visual Studio 2013. A known bug apparently:
+ * https://stackoverflow.com/questions/8146541/duplicate-external-static-declarations-not-allowed-in-visual-studio
+ */
+#if !defined(_MSC_VER)
static mbedtls_f_rng_t *const mbedtls_psa_get_random;
+#endif
/** The maximum number of bytes that mbedtls_psa_get_random() is expected to
* return.
