add external dependencies in a pre-built way to avoid incompatibilities

external/include/sodium/crypto_hash.h

@@ -0,0 +1,40 @@
+#ifndef crypto_hash_H
+#define crypto_hash_H
+
+/*
+ * WARNING: Unless you absolutely need to use SHA512 for interoperatibility,
+ * purposes, you might want to consider crypto_generichash() instead.
+ * Unlike SHA512, crypto_generichash() is not vulnerable to length
+ * extension attacks.
+ */
+
+#include <stddef.h>
+
+#include "crypto_hash_sha512.h"
+#include "export.h"
+
+#ifdef __cplusplus
+# ifdef __GNUC__
+#  pragma GCC diagnostic ignored "-Wlong-long"
+# endif
+extern "C" {
+#endif
+
+#define crypto_hash_BYTES crypto_hash_sha512_BYTES
+SODIUM_EXPORT
+size_t crypto_hash_bytes(void);
+
+SODIUM_EXPORT
+int crypto_hash(unsigned char *out, const unsigned char *in,
+                unsigned long long inlen) __attribute__ ((nonnull(1)));
+
+#define crypto_hash_PRIMITIVE "sha512"
+SODIUM_EXPORT
+const char *crypto_hash_primitive(void)
+            __attribute__ ((warn_unused_result));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif