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

external/include/sodium/crypto_verify_16.h

@@ -0,0 +1,23 @@
+#ifndef crypto_verify_16_H
+#define crypto_verify_16_H
+
+#include <stddef.h>
+#include "export.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define crypto_verify_16_BYTES 16U
+SODIUM_EXPORT
+size_t crypto_verify_16_bytes(void);
+
+SODIUM_EXPORT
+int crypto_verify_16(const unsigned char *x, const unsigned char *y)
+            __attribute__ ((warn_unused_result)) __attribute__ ((nonnull));
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif